Tech Tips

JUNE 2017

The Deutz 2.9L Tier 4 engines utilize a common rail fuel injection system.
The Skyjack Tech Tip

The Deutz 2.9L Tier 4 engines utilize a common rail fuel injection system. Gone is the familiar lift pump and injector pump arrangement. These engines use an electric fuel pump to deliver fuel through the filter to the high pressure fuel pump. The pump is mounted near the fuel tank near the replaceable cartridge fuel filter.

When the machine is powered up, the fuel pump runs to build pressure in the circuit. Once pressure is detected by the ECU sensor, it allows the engine to crank.

If you encounter a no crank/no fuel situation, check the following:

  1. Check that the circuit breaker CB3 is not tripped. This breaker is for the fuel pump only. Check the connections at the spades on the breaker; look for loose terminals and burnt or loose connections. Replace any wire terminals or the breaker itself if required. Do not assume the fuel pump itself is at fault. Check the fuel lines from the pump to the engine for any kinks, pinches or restrictions that can cause the fuel pump to work harder than normal.
  2. With the base and platform e-stops ON, key switch ON, check for power and ground at the fuel pump terminals located on the fuel pump or at the connector plug - if equipped. Make sure the terminals are clean and free of rust and debris that may cause a short. Clean or replace as needed.
  3. If power and ground are present at the fuel pump, check that the fuel pump is running. If not running, replace the fuel pump.
  4. If there is no power at the fuel pump, check the relay 56ACR located in the base control panel. The engine ECU supplies ground for the relay on wire 56A. If no ground is present, check the ECU harness and connectors. No ground at 56A may indicate an ECU problem.
  5. At the relay 56ACR, check wire 54 for power to the coil. With ground on 56A and power on 54 at the relay, you should read power at 56B wire direct to the fuel pump through a harness connector. Check power from the relay through the connector to the fuel pump.

Using this test procedure should help determine the cause of the problem – it is not always the fuel pump that is at fault. If you have questions or further problems please contact Skyjack Product Support at 1-800-275-9522 or email


************ REMEMBER THESE DATES! ************

JULY 17, 18, 19, 20, & 21st 2017:

On Monday July 17th, Tuesday July 18th, Wednesday July 19th, & Thursday July 20th:

On Friday July 21st:






Electrical connectors are an effective and durable way to make terminal connections
The Skyjack Tech Tip

Electrical connectors are an effective and durable way to make terminal connections at valve coils, wiring harness connections, and various other locations on equipment. Enclosed wiring terminals help to protect against corrosion-causing moisture, however, they can be susceptible to water intrusion. Time, pressure washing, improper or loose re-assembly, and damage are all factors that contribute to failure of a connector.

Once a connector is corroded, it can be difficult to clean and service the part completely back to original condition. Any part that has been damaged by corrosion will likely fail again. Keeping the connectors tight, clean, and sealed will help to prevent this damage

When checking any connector, inspect it for damage or improper assembly. Make sure the wire entrance, (strain relief) is tight and no places exist where water can intrude. Examine any latches or locks for damage or incorrect assembly. Open the connector and check for corrosion at the terminal contacts and wire connections. Look for loose wire connections and damaged wires. Correct any problems and if necessary, replace the connector. When inspecting or replacing the part, apply some dielectric grease to the wire terminals and the terminal contacts to prevent corrosion. If water does get in, the dielectric grease will help to prevent corrosion problems.

A little preventive maintenance on any electrical connectors will ensure that the connector will remain clean and intact for a long time. Ensuring that connections are properly maintained helps you to provide a safe and dependable piece of equipment that will satisfy your customer each time they use it.

If you have any questions regarding your Skyjack product, please contact Skyjack Product Support at 1-800-275-9522 or email

Technicians be aware! There are new North American (ANSI and CSA) standards on the horizon. These new standards will affect machine operation and capabilities. It is a good idea to familiarize yourself with the new standards to be prepared for upcoming changes in order to do your job correctly and effectively. You can look at the information at

New Models

It is every technician’s responsibility to keep up-to-date on the new equipment’s proper and safe operation.
The Skyjack Tech Tip

Skyjack is constantly improving and developing new products for our customers. We recently added a motor controller option to our electric scissor models and have redesigned our telehandler line with the new TH series. The T and AJ model boomlifts are still relatively new with an 86-foot straight stick boom being the latest addition. An 85-foot articulating boom will debut soon.

When new models and designs are implemented, there are often different functions and capabilities that the equipment can perform. It is every technician’s responsibility to keep up-to-date on the new equipment’s proper and safe operation. This means taking the time to educate yourself about any new equipment. The old adage, “you can’t fix it if you do not know how it works” comes into play here. If you do not know if the equipment is performing a function properly or if a circuit is working correctly, you would not know if it needs to be repaired or adjusted. This lack of equipment knowledge can lead to problems with unsafe equipment operation or incorrect adjustment of parts that can cause premature wear of components or damage.

The operator’s manual and the service manual are tools a technician can use to accomplish this. The service and operation manuals provide test procedures and operation instructions and descriptions that are to be used when maintaining the equipment. Always use the correct manual for the serial number of the unit you are servicing to assure you have the correct information at hand. The manuals are available at our website, or on an updatable flash drive available from parts department as part number 167847.

If you ever have any questions regarding an older or newer Skyjack product, please contact Skyjack Product Support at 1-800-275-9522 or email

One of the most important maintenance items for any of the telehandler models is proper lubrication. When servicing the unit always use the decals on the unit and/or the service manual for the location of all the lube points, proper intervals, and the correct lubricant to use.


Wheel assemblies and their connection to the machine must be checked.
The Skyjack Tech Tip

As a required part of each inspection, wheel assemblies and their connection to the machine must be checked. This includes looking for any signs of damage and ensuring that the wheel bolts are properly tightened. If any wheel bolts are found to be loose or not at the correct torque value of 90 ft-lb (122 Nm), each component (wheel rim, wheel bolts, hub) should be inspected to ensure that there is no damage, prior to re-assembly. Do not attempt to re-tighten damaged parts – they must be replaced.

When replacing or re-installing a wheel/tire or wheel bolt, ensure that all the mounting surfaces are clean and free of any debris, rust, excess paint, etc. Mount the wheel on the hub, centering the mounting holes on the bolt holes as shown in Figure 1.

Figures 1 & 2

Install the wheel bolts and hand tighten to center the rim on the hub. Next, torque the bolts to approximately 50 ft-lb (68 Nm) in the tightening sequence shown in Figure 2. Torque the wheel bolts again to their final torque of 90 ft-lb (122 Nm) using the same sequence. Repeat the tightening sequence to confirm that none of the wheel bolts have changed from 90 ft-lb (122 Nm). If any wheel bolts have changed in value, repeat the complete torqueing sequence until there is no change in torque values. If possible, drive the machine prior to checking the torque values.

The regular and required checks of the wheel bolt torque will ensure that the wheels remain secure and that damage to the assembly will not occur.

To aid operators conducting daily inspections ensuring tightness of the wheel/tire assembly, torque seal paint, wheel nut indicators or other visual indicators may be used.

If you have any questions regarding your Skyjack product, please call Skyjack Product Support at 1-800-275-9522 or email


Pothole Protection Maintenance

The pothole protection system is designed to reduce ground clearance...
The Skyjack Tech Tip

The pothole protection system on the Skyjack SJIII model DC electric scissor lifts is designed to reduce ground clearance and assist in the stability of an elevated aerial platform in the event the aerial platform encounters a “drop-off” or “pothole.” As with all safety devices, periodic inspection and maintenance is required to ensure the proper operation of the pothole protection device. The nature of this safety feature relies on maintaining a consistent ground clearance, therefore, if the aerial platform ever does come in to rest on the pothole device, the platform should be immediately lowered and “locked out” to prevent further use until a complete inspection of the mechanism is performed by a qualified technician.

The system is comprised of four major components; the pothole bar (not shown), the camlock assembly, the compression rods, and the limit switches. See Figure 1.

Figure 1

The pothole bars are the angle parts located along the bottom edge of the tray on each side of the unit. They deploy by gravity and should pivot smoothly and not be bent or damaged.

The most important part of maintaining the system is keeping it clean. Familiarize yourself with how the mechanism correctly operates. Examine the mechanism for damage and debris. Replace any worn or damaged parts. Thoroughly clean the entire mechanism – a pressure washer works best to remove any material that may prevent smooth operation of the mechanism. Operate the mechanism and look for smooth operation of the levers, pothole bars, and camlocks. Test for correct operation by placing a block (approximately 1.5” high) under the swing out tray on one side (preventing the pothole mechanism from fully-deploying). After raising the platform to a height of approximately 7 feet, attempting to drive should result in no movement. This test should be repeated for the other pothole bar.

No lubrication is needed for the camlock assembly as it uses oil impregnated bushings. The same applies to the pothole bar pivots under the trays, they use the oil impregnated bushings as well and require no lubrication. Sparingly apply a light spray lube on the limit switch roller plunger, and the pivot pins - too much will attract dirt and debris since this mechanism is close to the ground.

For more information regarding the pothole mechanism limit switch adjustment, or replacing the camlock assembly, please visit, look under technical manuals and input your model OR serial number and watch the technical animations for those procedures. If you have any questions regarding your Skyjack product, please contact Skyjack Product Support at 1-800-275-9522 or email for assistance.

Training for your technicians is very necessary to maintain a dependable and safe fleet. Technical training is available for current production equipment at your location from your Skyjack Regional Service Representative. For more information, ask your rep when they stop by, or call 1-800-275-9522 and ask for Rich Soltas. You can also email

Deutz 2.9L Trouble Codes

The new Deutz 2.9L Tier 4 diesel engines are capable of providing the technician with a flash code for engine diagnostics
The Skyjack Tech Tip

The new Deutz 2.9L Tier 4 diesel engines are capable of providing the technician with a flash code for engine diagnostics to assist the technician when a computer is not available. The platform and base control panels are equipped with a warning light display to alert the operator of problems. Consult the correct operating or service manual for the model and serial number of the machine you are working on for the location and identification of the lights.

When looking at the warning lamp, it will display either a continuous light or a flashing light.

A continuous light refers to a system error; likely an engine sensor, for example the coolant temperature sensor or oil pressure sensor signal to the ECU is out of range. This is considered a non-critical fault and the ECU allows continued operation but may reduce engine power.

A flashing warning indicates a serious error. The operator should shut the engine off. The ECU will reduce engine power and shut down the engine after a certain time and in some cases may let the engine run at reduced power for a short time to cool the engine - then shut it down.

To retrieve a flash code, find the diagnostic switch located on the base control console. Turn on the power for the unit, (do not start) and hold the switch until the warning light begins to flash. Immediately start counting the flashes. The codes are a 3-digit code and are shown as a series of flashes. The first digit will be short/quick flashes followed by a 2 second pause. The second digit will be longer/slower flashes followed by a 2 second pause. The third digit will be shown as the short/quick flashes followed by a 5 second pause. Any more codes stored will be shown in order of occurrence and it will repeat the first code once all have been displayed.

Once you have the codes recorded, contact your local Deutz dealer or call Skyjack Product Support at 1-800-275-9522 or e-mail for assistance.

After the problem is corrected, the code should clear from the list and the light should go off. If it does not contact your local Deutz dealer.

All of us here at Skyjack Product Support would like to wish you all a very Happy Holiday, and we look forward to a peaceful and prosperous New Year.


Each terminal block can hold four conductors of the same circuit.
The Skyjack Tech Tip

The electrical circuit terminal blocks used in the Skyjack Aerial Work Platforms are a method to neatly and securely terminate wires of the same circuit at a common point. Each terminal block can hold four conductors of the same circuit. Each block is attached to a metal rail mounted to the panel or control box and are ‘stacked’ side by side to form one terminal strip assembly.

Figure 1 shows a single block from the top as you would see it in a machine. Figure 2 shows the block from the side and you can see the spring clips that secure the wires inside the block and how all four wire holes connect to each other.

Figure 1 & 2
To insert or remove a wire from the block, insert a thin blade screwdriver into the slot adjacent to the desired wire location and push in firmly. This pushes the spring metal clip away from the wire end and the wire can be inserted or removed from the round hole. See figure 3.
Figure 3

To test a circuit at the terminal block with a voltmeter probe, insert the probe into either the insertion tool slot to contact the spring clip, or use the jumper slots next to the wire number tag area.

Some of the terminal blocks are equipped with an internal diode. These blocks have a diode symbol in the middle of the block. The diode separates two round wire holes from the opposite two holes. Figure 4 shows the diode-equipped terminal block.

Figure 4

Knowing how the terminal blocks work will make troubleshooting electrical circuits easier and more accurate.

If you have any questions regarding your Skyjack product, please contact Skyjack Product Support at 1-800-275-9522 or email


3 Tips for Easier Troubleshooting

Here are 3 tips to make your troubleshooting easier with Skyjack machines.
The Skyjack Tech Tip

1. When troubleshooting any of the new Motor Controlled Vertical Mast or Electric Powered Scissor Lifts, make sure you have good, clean & tight ground connections. A bad ground connection anywhere in the circuit can be the root cause of the malfunction. When taking volt readings please use the B- terminal at the motor controller. This is direct from the negative battery terminal.

2. When operating or testing a Skyjack vertical mast, scissorlift, or boomlift, please make sure both the base control panel and platform control panel emergency stop switches are turned on. The units will not operate with one emergency stop in the on position.

3. When checking the auto level system on the Skyjack rough terrain scissor models, use the red LED on the auto level module to tell you the system status. When the LED is off, the outriggers are fully retracted. A solid LED indicates outriggers are extended and the unit is level. The LED will flash when the outriggers are in operation — extending or retracting. If you have a flashing LED and the outriggers are not being operated, the LED is sending an error code. Please consult the chart in correct service manual for the serial number of the unit you are working on.

If you have any questions regarding your Skyjack product, please contact Skyjack Product Support at 1-800-275-9522 or e-mail

When replacing the batteries on your electric scissorlift or vertical mast model, please remember to use the correct specification replacement battery for that machine. Using a smaller battery for example, would not provide the needed power and amp hours which could damage the electrical components. Most importantly, the battery weight is part of the ballast for the machine and is critical to proper stability when elevated.

Proportional Joystick Tests

The joystick on our Vertical Mast and Electric Scissor lifts have two outputs.
The Skyjack Tech Tip

When testing the joystick output for the drive or lift function on a Skyjack Vertical Mast or Electric Scissor lift model, you need to know the joystick has two outputs. One output is a system voltage output to operate the pump motor, valve coils, and relays. The other output is the speed, or proportional signal. This is a variable output signal relating to the speed desired for the function.

To test the system voltage output, locate the ‘A’ and ‘B’ wires at the LIFT-OFF-DRIVE function selector switch. The ‘A’ output is a purple/white color wire and it should have system voltage on it when the joystick handle is moved backward for reverse drive or platform lowering. The ‘B’ output is a solid red color wire and has power when the joystick handle is moved forward for forward drive or platform lift. If no power is seen at the selector switch, look for a diode inline on the ‘A’ and ‘B’ wires. A shorted open diode would prevent power reaching the selector switch. If no power is found, try operating the steer function to verify that the enable circuit is working. If no steer, test the enable switch circuit.

To test the proportional output, check power at the orange/black color wire 59 at the joystick 9-pin connector. You should read a proportional output that increases as the handle is moved farther away from neutral. For the SJIII hydraulic proportional units, the wire 59 output will vary from zero to 13.5/14volts at full handle throw on a properly adjusted joystick. For the Vertical Mast and SJIII Motor Controller (MC) units, the output will vary from zero to 4.6 at the joystick connector.

Please note that all the joysticks are not the same. Different models and configurations have different part number joysticks. Please consult the correct service or parts manual for the serial number of the model you are working on for the correct replacement joystick. Manuals are accessible at our website, or an updatable flash drive available from our parts department. Part number 167847.

If you have questions regarding your Skyjack aerial lift or telehandler, please contact Skyjack Product Support at 1-800-275-9522 or email

Warning and indicator lights are a very important part of safe operation of any piece of equipment. Any and all warning and indicator lights should be checked at each inspection. Any inoperable LEDs or burned out bulbs should be replaced. These lights are as critical to safe operation as the safety limit switches and warning and instruction decals. Please do not overlook them.

Throttle and choke pull solenoids

Many of the engines we use in our scissorlift and boomlift models utilize a simple pull solenoid
The Skyjack Tech Tip

Many of the engines we use in our scissorlift and boomlift models utilize a simple pull solenoid to operate the engine throttle and choke. The solenoid consists of a steel plunger that is placed inside a wound coil of copper wire. When this coil is energized, a magnetic field is produced which draws the plunger into the magnetic field. The other end of the plunger is connected to the throttle or choke lever to be operated.

The majority of the solenoids we use are generically known as dual-coil, internally switched devices. Dual-coil solenoids have two coil windings: a ‘pull’ coil and a ‘hold’ coil. The pull coil is a large winding, and energizing this winding produces the solenoids maximum pull force and is used to initially retract the plunger. The hold coil is a smaller winding which produces a weaker pull force and is used to hold the plunger in its retracted position.

When the solenoid is activated, both coils are powered to produce the strongest pull force possible. Once the plunger is fully retracted, power to the pull coil is shut off and only the hold coil is powered to hold the plunger in place. To accomplish this, when the plunger is fully retracted into the solenoid body, it makes contact with an internal switch in the bottom of the bore which opens the circuit to the pull coil; depowering it.

The most common cause of solenoid failure is incorrect adjustment of the plunger and linkage resulting in burnout. If the plunger does not bottom out in the solenoid bore, the internal switch will not open the circuit to the pull coil. Because of the high amp draw of the pull coil, if it remains powered for a long period of time it will heat up and literally ‘cook’ the solenoid internally. A burned out solenoid can cause the main circuit breaker to trip, shutting down the machine or not having any high throttle function.

When installing or replacing the solenoid, make sure the solenoid is mounted securely and the plunger movement is in a straight line with the lever to be actuated. Check under the solenoid boot and make sure there is no spring under it. If a spring is present, remove it. Manually pull the plunger into the solenoid, making sure it is completely ‘bottomed out’ in the bore, this will insure the internal switch is opened - breaking power to the pull coil. While holding the plunger in that position, adjust the clevis on the threaded end of the plunger to set the throttle or choke lever to the proper position. Lock the clevis into place and test the solenoid operation. Make sure the lever being actuated is moving freely so the solenoid can pull it easily. Then check that the solenoid plunger is not allowed to move out of the solenoid body too far; or the magnetic field will not be able to pull it in. The solenoid mounting may have to be adjusted to accomplish this. Proper solenoid installation and set-up is critical to proper operation and long life.

At Skyjack Product Support, we want your Skyjack equipment to operate safely and dependably. If you have any questions regarding your Skyjack product, please contact product support at 1-800-275-9522, or e-mail

Skyjack aerial work platforms must have any associated service bulletins completed prior to passing their annual inspections. When performing a frequent or annual inspection, it is a good idea to contact Skyjack Product Support to check for any open service bulletins related to the machine’s serial number. Call Skyjack product support at 1-800-275-9522 and have your serial number ready and we will check to see if any bulletins apply to that machine.

Filter by year

Popular Tags
  • Boom lift
  • Tilt switch
  • ANSI
  • SJIII Series
  • Vertical Mast lift
  • key switches
  • Deutz
  • Connectors
  • installation
  • service manual
  • Flash Drive
  • hydraulics
  • solenoid
  • Download
  • pump motor
  • copper wire
  • MC
  • maintenance
  • Spring mounted
  • Series III

Search Bulletins

Please enter your Skyjack serial number to check for Service Bulletins for your machine:
Please enter the bulletin


Service bulletins for serial number