U0167 Lost Communication With Vehicle Immobilizer Control Module

OBD-II Trouble Code - U0167 - Data Sheet

U0167 - Disruption of communication with the vehicle immobilizer control module

What does DTC U0167 mean?

This is a generic communications system diagnostic trouble code that applies to most makes and models of OBD-II vehicles.

This code means that the vehicle immobilizer control module (VICM) and other control modules on the vehicle do not communicate 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 vehicle immobilizer control module is usually located behind the dashboard or inside the steering column. 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 control the starting of the vehicle.

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 because of the safety issues that can arise from the VICM causing a condition in which the engine does not start.

Symptoms of a U0167 code may include:

• Malfunction Indicator Light (MIL) is on
• May work fine until restarted; then won't restart
• The engine will start but immediately stall; won't run
• Engine light on (or service engine warning light)

Causes of error U0167

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 VICM
• Rarely - the control module is faulty
• Faulty immobilizer control module
• Immobilizer control module harness is open or shorted.
• Faulty immobilizer control circuit
• Malfunctioning engine control module (ECM) What does this mean?

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 U0167 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 U0167, try accessing the Vehicle Immobilizer Control Module (VICM). If you can access codes from VICM then code U0167 is either intermittent or memory code. If you cannot access the VICM, then code U0167 that other modules install is active and the problem already exists.

The most common malfunction is a loss of power or grounding of the vehicle immobilizer control module.

Check all fuses supplying the VICM on this vehicle. Check all the grounds for VICM. 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 U0167 returns or you can contact the VICM. If no code returns or connectivity 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 VICM connector, which is usually found behind the dashboard or inside the steering column. Disconnect the negative battery cable before disconnecting the connector on the VICM. 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.

Perform these few voltage checks before connecting the connectors back to the VICM. You will need access to a digital volt/ohmmeter (DVOM). Make sure you have power and ground at the VICM. Access the wiring diagram and determine where the main power and ground supplies enter the VICM. Reconnect the battery before continuing with the VICM still disabled. Connect the red lead of the voltmeter to each B+ (battery voltage) power supply entering the VICM connector, and the black lead of the voltmeter to a good ground (if 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 U0167, the only thing that can be done is to seek help from a trained automotive diagnostician as this will indicate a failure of the VICM. Most of these VICMs must be programmed or calibrated to fit properly in a vehicle.

U0167 DESCRIPTION LAND ROVER

This DTC is stored in the control module when communication is lost or the message is corrupted. Communication protocols have strict error handling processes when transmitting data. If a module or component that can communicate on the data bus returns a negative acknowledgment, an error flag will be set and the module that is transmitting invalid data may be disconnected from the network.

DTC Jeep U0167 Short Explanation

Need more help with the U0167 code?

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