Jaguar: No Communication With Modules After Reconnecting Battery

Jaguar: No Communication With Modules After Reconnecting Battery

If the battery supply to the vehicle is disconnected for any reason, the Chassis Control Module may not power-up correctly.

Models: XJ/X351, XF/X250 with air suspension

Issue: If the battery supply to the vehicle is disconnected for any reason, the Chassis Control Module (also known as the Air Suspension Module or Suspension Module Integrated Suspension Control Module (CHCM) may not power-up correctly. As a result, a scan tool will report no communication with the CHCM module in several session screens. This will only affect a small percentage of cars and on an intermittent basis.

The vehicle may also display error messages on the cluster relating to suspension and adaptive dynamics faults: “SUSPENSION FAULT Max Speed 30 MPH” or “Adaptive Dynamics Fault.” The SDD tool may also log code U012A-00 from modules which communicates with the CHCM.

Cause: The power-up strategy currently in place for the CHCM and CHCMB can cause this concern.

Action: To resolve the issue, fully disconnect the negative lead from the battery terminal. Wait for 5 minutes and re-connect the battery negative. Repeat this process if necessary. Ensure that a power supply unit is NOT connected to the vehicle when doing this. A scan tool should confirm communication with the CHCM and CHCMB (note: the CHCMB is optional) and cluster error messages will no longer appear.

You May Also Like

VarioCam: Understanding Porsche’s VVT Technology

Originally developed for the 2001 Porsche 911 Turbo, VarioCam changes the valve timing to increase power & reduce emissions.

VarioCam and VarioCam Plus are Porsche’s patented variable valve timing and valve lift technologies that have evolved over the past two decades. Originally developed for the 2001 Porsche 911 Turbo, VarioCam changes the valve timing to increase power and reduce emissions. 

VarioCam Plus on later models can adjust valve lift by controlling oil to the upper part of the lifter. The lifter can ride on two different profiles on the camshaft. But, the oil passages can become clogged if an oil change is neglected.

Mercedes 4MATIC Diagnostics

The Mercedes-Benz 4MATIC all-wheel drive (AWD) systems have been around for a while now.

Mercedes-Benz Auxiliary Water Pump Diagnostics

These pumps will show up on more and more vehicles as engines become more efficient and generate less excess heat.

Timing BMW VANOS N53 And N54 

To service them, you will need the appropriate toolset to lock the crank and camshaft.

Jaguar V6 Timing Chain Service

When a guide and tensioner fail, it induces timing chain slap that causes the chain to jump on the sprockets.

Other Posts

Active Suspension Service 

An active dampener allows for a ride without compromise.

Mercedes-BMW-Jaguar-suspension-1
Volvo Engine Service

There are many combinations for the Volvo modular engine.

Servicing Mercedes-Benz AMG Brakes

Take a look at some of the things you need to know in order to service the brakes on a Mercedes-Benz AMG vehicle.

AUDI Outside Air Temperature Readings

Incorrect readings can be avoided.