U0160 Lost Communication With Sound Alert Control Module
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U0160 Lost Communication With Sound Alert Control Module
OBD-II DTC Datasheet
Lost Communication With Sounder Control Module
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 Alert Control Module (AACM) 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 AACM is usually located behind the dashboard, usually in the center of the vehicle. 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 sound an alert to the driver based on vehicle proximity, lane departure, or even parking assistance.
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 medium due to the safety problems that arise from the fact that the AACM may give incorrect information about obstacles on the vehicle.
Symptoms of a U0160 code may include:
- Sound alert control module does not alert when needed / always alerts
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 on AACM
- 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 U0160 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 U0160, try accessing the audible alert control module. If you can access codes from AACM, then code U0160 is either intermittent or memory code. If the AACM cannot be accessed, then code U0160 set by other modules is active and the problem already exists.
The most common failure is a loss of power or ground to the AACM.
Check all fuses supplying the AACM on this vehicle. Check out all the reasons for AACM. 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 U0160 returns or you can contact the AACM. If no code is returned or communication is restored, the problem is most likely a fuse / connection issue.
If the code returns, locate the CAN bus connections on your vehicle, most importantly the AACM connector, which is usually located behind the dashboard, in the center of the vehicle. Disconnect the negative battery cable before disconnecting the connector on the AACM. 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 AACM. You will need access to a digital volt/ohmmeter (DVOM). Make sure you have power and ground on the AACM. Access the wiring diagram and determine where the main power and ground sources enter the AACM. Connect the battery before continuing with AACM still disabled. Connect the red lead of your voltmeter to each B+ (battery voltage) power supply going into the AACM 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 clear DTC U0160, the only thing that can be done is to seek help from a trained automotive diagnostician as this will indicate an AACM failure. Most of these AACMs must be programmed or calibrated to fit properly on a vehicle.
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