U0131 Lost Communication With Power Steering Control Module (PSCM)

OBD-II Trouble Code - U0131 - Data Sheet

U0131 Lost Communication With Power Steering Control Module (PSCM)

What does DTC U0131 mean?

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

This code means the power steering control module (PSCM) 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 PSCM accepts input from various sensors, some of which are directly connected to it and some are sent over a bus communication system. These inputs allow the module to provide an electric power steering system or an electro-hydraulic variable power steering system. These systems only provide assistance as there is still a mechanical link to the steering system. These auxiliary systems can be fully electronically controlled or electronically controlled hydraulic systems, depending on the manufacturer's application.

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.

Severity and symptoms

The severity in this case depends on the system. Since the system can be an electric power steering system or an electro-hydraulic power steering system with variable power steering, the severity may be minor in one system, but can be a major safety issue in the absence of power steering in another.

Symptoms of a U0131 engine code may include:

• Fault indicator light is on
• Loss of power steering

Causes of error U0131

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
• Loss of power or ground to the PSCM - the most common
• 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.

If your scan tool can access trouble codes and the only code you are pulling from other modules is U0131, try accessing the PSCM. If you can access the codes from the PSCM, then code U0131 is either intermittent or a memory code. If the codes for the PSCM cannot be accessed, then code U0131 that other modules set is active and the problem already exists.

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

Check all fuses supplying the PSCM on this vehicle. Check all grounds for the PSCM. Locate grounding attachment 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 U0131 returns or you can contact the PSCM. 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 C bus connections on your specific vehicle, especially the PSCM connector. Disconnect the negative battery cable before disconnecting the connector on the PSCM. 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 electrical grease where the terminals touch.

Perform these few voltage checks before plugging the connectors back into the PSCM. You will need access to a digital volt-ohmmeter (DVOM). Make sure you have power and ground on the PSCM. Access the wiring diagram and determine where the primary power and ground supplies go into the PSCM. Reconnect the battery before proceeding with the PSCM still disabled. Connect the red wire of your voltmeter to each B + (battery voltage) power source going to the PSCM connector, and the black wire of your voltmeter to a good ground (if unsure, the negative pole of the battery always works). You can see the battery voltage reading. Make sure you have a good reason. Connect the red lead from the voltmeter to battery positive (B +) and the black lead to each ground. Once again, you should see the battery voltage every time you plug it in. If not, troubleshoot the power or ground circuit.

Then check the two communication circuits. Locate CAN C+ (or HSCAN+) and CAN C- (or HSCAN - circuit). With the black wire of the voltmeter connected to a good ground, connect the red wire to CAN C+. With the key on and engine off, you should see about 2.6 volts with little fluctuation. Then connect the red wire of the voltmeter to the CAN C- circuit. You should see about 2.4 volts with little fluctuation. Other manufacturers show CAN C- at about 5V and an oscillating key with the engine off. Check your manufacturer's specifications.

If all tests pass and communication is still not possible, or you were unable to reset DTC U0131, the only thing to do is to seek help from a trained automotive diagnostician, as this will indicate a faulty PSCM. Most of these PSCMs must be programmed or calibrated for the vehicle in order to be properly installed.

 Code U0131 Brand specific information

• U0131 Acura F-CAN Malfunction Engine Control Module - Power Steering Control Module
• U0131 Buick lost communication with power steering control module
• U0131 Cadillac lost communication with power steering control module
• U0131 Chevrolet lost communication with power steering control module
• U0131 Ford lost communication with power steering control module
• U0131 GMC lost communication with power steering control module
• U0131 Honda F-CAN Malfunction Engine Control Module - Power Steering Control Module
• U0131 Lincoln lost communication with power steering control module
• U0131 Mercury lost communication with power steering control module

Hard Power Steering Wheel Honda Sity ivtec | EPS Hard | Error Code U0131

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