ABS - Control Module Internal Fault Diagnosis
No: LM100-004Issue: 1
Date: 01 Dec 06
SECTION: 100-00 - GENERAL INFORMATION
Internal Control Module Faults Relating to the ABS Module Diagnosis
AFFECTED VEHICLE RANGE:
New Range Rover (LM) VIN: 3A101029 onwards
CONDITION SUMMARY:
DIAGNOSTICS GUIDANCE FOR INTERNAL CONTROL MODULE FAULTS RELATING TO ABS MODULE DIAGNOSIS
Situation: This bulletin has been issued to provide diagnostic guidance for internal control module faults relating to an Anti-lock Braking System (ABS) module diagnosis.
Action: Should a DTC for an ABS/DSC module indicate any form of 'internal control module error', refer to the Repair Procedure detailed in this bulletin to resolve the concern.
PARTS:
No parts required for this bulletin. Diagnostic information only.
WARRANTY:
No warranty provided for this bulletin. Diagnostic information only. Normal warranty policy and procedures apply.
REPAIR PROCEDURE
INTERNAL CONTROL MODULE ERRORS RELATING TO THE ABS MODULE
NOTE: 'Internal control module errors' may be the result of components within the ABS/Dynamic Stability Control (DSC) module. These may include problems with the microprocessor, power supply or driver circuit (e.g. valve driver circuits). Internal control module errors are usually a good indication of a genuine control module fault, but can sometimes be logged as a result of other faults that are external to the control module.
NOTE: After following the guidance in this bulletin, if no definite cause was found for an internal control module DTC, and the vehicle does not have a history of repeat failures, and all DTCs have been cleared and have not returned after a test drive of at least 10 miles (16 km), the vehicle can be returned to the customer.
IDENTIFY AND RESOLVE FAULTS
NOTE: A Midtronics battery charger PSC550 must be connected to the vehicle battery during diagnostic sessions.
1. Connect the diagnostic equipment to the vehicle and begin a WDS or IDS session.
NOTE: DTCs and snap shot data should be noted at all stages during the diagnosis. This information will be needed in the event further assistance is requested from Land Rover Technical Helpline.
2. Note DTCs and collect snap shot data.
NOTE: Faults may be either 'permanent' or 'intermittent'. Intermittent faults can be difficult to find but are usually caused by wiring or connector issues. A 'permanent' fault may indicate that a control module has internal damage. If internal damage is discovered, the module should be replaced.
A fault may be determined to be either 'permanent' or 'intermittent by using the diagnostic tool to clear the Diagnostic Trouble Code (DTC) and carrying out an ignition reset or completing a short drive cycle. A short drive cycle involves driving the vehicle in a straight line up to a speed of 15 mph (24 kph).
3. Determine if a fault is 'permanent' or 'intermittent' as follows:
^ Clear the DTC.
^ Carry out an ignition reset.
^ If the fault immediately returns on the next ignition reset or short drive cycle, and if it is the only fault that returns, the fault is 'permanent' and the control module should be replaced.
NOTE: Internal control module errors can be caused by corrupted sensor or Controller Area Network (CAN) information being fed into the control module. A faulting sensor may be the cause of these errors but will typically log other DTCs in addition. It is necessary to investigate the cause of any other DTCs and fix the issues causing them before going any further. Resolving a problem causing other DTCs may also resolve the 'internal control module error'.
4. Resolve DTCs that are not flagged as an 'internal control module error'.
5. Verify if the DTC resolutions have cleared the 'internal control module error' DTC.
NOTE: Internal control module errors can be caused by poor or intermittent contact to power or ground. The integrity of the control module power and ground connections should therefore be checked. Check for continuity and short circuits. Where possible, flex wires while checking to search for intermittent faults. 'internal control module errors' are more likely to be caused by electrical 'spikes' than by prolonged power/ground breaks.
6. Check the integrity of the control module power and ground connections.
7. Check for continuity and short circuits while flexing wires, where possible, to search for intermittent faults.
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