U0158 Lost Communication With Projection Display
OBD2 Error Codes

U0158 Lost Communication With Projection Display

U0158 Lost Communication With Projection Display

OBD-II DTC Datasheet

Lost Communication With Head Up Display

What does this mean?

This is a generic communication system diagnostic trouble code that applies to most makes and models of vehicles.

This code means the head-up display (HUD) and other control modules on the vehicle are not communicating with each other. The circuitry most commonly used for communication is known as Controller Area Bus communication, or simply the CAN bus.

Without this CAN bus, control modules cannot communicate and your scan tool may not receive information from the vehicle, depending on which circuit is involved.

The HUD is usually located behind the dashboard, usually in the center of the vehicle, facing the windshield. It receives input data from various sensors, some of which are directly connected to it, most of which are transmitted via a bus communication system. These inputs allow the module to display information on the windshield for easier viewing.

Troubleshooting steps may vary depending on the manufacturer, the type of communication system, the number of wires, and the colors of the wires in the communication system.

Code severity and symptoms

The severity in this case is always serious due to the safety issues that arise from the fact that the HUD can obstruct the driver's view.

Symptoms of a U0158 code may include:

  • Heads Up Display no info / blank screen

reasons

Usually the reason for installing this code is:

  • Open in CAN + bus circuit
  • Open in the CAN bus - electrical circuit
  • Short circuit to power in any CAN bus circuit
  • Short to ground in any CAN bus circuit
  • No power or ground to HUD module
  • Rarely - the control module is faulty

Diagnostic and repair procedures

A good starting point is always to check the Technical Service Bulletins (TSB) for your particular vehicle. Your problem may be a known issue with a known manufacturer-released fix and could save you time and money while troubleshooting.

First, look for other DTCs. If any of these are bus communication or battery / ignition related, diagnose them first. Misdiagnosis is known to occur if you diagnose the U0158 code before any of the major codes are thoroughly diagnosed and rejected.

If your scan tool can access trouble codes and the only code you are getting from other modules is U0158, try accessing the HUD. If you can access the codes from the HUD, then code U0158 is either intermittent or a memory code. If you can't access the HUD, then code U0158 that other modules are setting is active and the problem already exists.

The most common failure is loss of power or ground to the HUD.

Check all fuses supplying the HUD module on this vehicle. Check out all the reasons for the HUD. Locate ground anchorage points on the vehicle and make sure these connections are clean and secure. If necessary, remove them, take a small wire bristle brush and baking soda / water solution and clean each one, both the connector and the place where it connects.

If any repairs have been made, clear the DTCs from memory and see if U0158 returns or you can contact the HUD module. If no code is returned or communication is restored, the problem is most likely a fuse / connection issue.

If the code returns, look for the CAN bus connections on your vehicle, especially the HUD connector, which is usually located behind the dashboard. Disconnect the negative battery cable before disconnecting the connector on the HUD module. Once detected, visually inspect the connectors and wiring. Look for scratches, scuffs, exposed wires, burn marks, or molten plastic.

Disconnect the connectors and carefully inspect the terminals (metal parts) inside the connectors. See if they look burnt or have a green tint indicating corrosion. If you need to clean the terminals, use an electrical contact cleaner and a plastic bristle brush. Allow to dry and apply dielectric silicone grease where the terminals touch.

Before connecting the connectors back to the HUD, perform these few voltage checks. You will need access to a digital volt/ohmmeter (DVOM). Make sure you have power and ground on the HUD. Access the electrical diagram and determine where the main power and ground sources enter the HUD. Reconnect the battery before proceeding with the HUD still disabled. Connect the red lead of your voltmeter to each B+ (battery voltage) power supply going into the HUD connector, and the black lead of your voltmeter to a good ground (if you're unsure, battery negative always works). You should see the battery voltage reading. Make sure you have a good reason. Connect the red lead of the voltmeter to the battery positive (B+) and the black lead to each ground circuit. Once again, you should see the battery voltage every time you connect. If not, repair the power or ground circuit.

Then check the two communication circuits. Locate CAN B+ (or MSCAN + circuit) and CAN B- (or MSCAN - circuit). With the black wire of the voltmeter connected to a good ground, connect the red wire to CAN B+. With the key on and the engine off, you should see a voltage of about 0.5 volts with little fluctuation. Then connect the red lead of a voltmeter to the CAN B circuit. You should see about 4.4 volts with slight fluctuations.

If all tests pass and communication is still not possible, or you were unable to reset DTC U0158, the only thing to do is to seek help from a trained automotive diagnostician, as this will indicate a HUD failure. Most of these HUDs must be programmed or calibrated in order to properly mount the vehicle.

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