U0162 Lost communication with navigation display module

OBD-II DTC Datasheet

Lost Communication With Navigation Display Module

What does this mean?

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

This code means the Navigation Display Module (NDM) 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 navigation display module is usually located behind the dashboard, usually in the center of the vehicle, although in some vehicles it may be installed in the trunk. It accepts input data from various sensors, some of which are directly connected to it, and most are transmitted over a bus communication system. These inputs allow the module to display the correct routing information.

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 security concerns that arise from the NDM's ability to provide incorrect navigation information.

Symptoms of a U0162 code may include:

Navigation system no information / blank screen
Navigation system does not work

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 NDM 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 U0162 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 U0162, try accessing the navigation display module. If you can access codes from NDM, then code U0162 is either intermittent or memory code. If the NDM cannot be accessed, then code U0162 set by other modules is active and the problem already exists.

The most common failure is a loss of power or ground to the navigation display module.

Check all fuses supplying the NDM on this vehicle. Check all grounds for NDM. 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 U0162 returns or you can contact the NDM 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 communication connections on your vehicle, most importantly the NDM connector, which is usually located behind the dashboard, usually in the center of the vehicle, although in some vehicles it may be installed in the trunk. Disconnect the negative battery cable before disconnecting the NDM connector. 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 NDM. You will need access to a digital volt/ohmmeter (DVOM). Make sure you have power and ground at the NDM. Access the electrical diagram and determine where the main power and grounds enter the NDM. Reconnect the battery before proceeding with NDM disabled. Connect the red lead of your voltmeter to each B+ (battery voltage) power supply included in the NDM connector, and the black lead of your 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 U0162, the only thing that can be done is to seek help from a trained automotive diagnostician as this will indicate an NDM failure. Most of these NDMs must be programmed or calibrated in order to properly install the vehicle.

Related DTC discussions

There are currently no related topics in our forums. Post a new topic on the forum now.

Need more help with the U0162 code?

If you still need help with DTC U0162, post a question in the comments below this article.

NOTE. This information is provided for informational purposes only. It is not intended to be used as a repair recommendation and we are not responsible for any action you take on any vehicle. All information on this site is protected by copyright.