Diagnosis and check 4.0L (Discovery 3)

Review

Turbocharged engines have 2 accessory drive belts; this section describes basic checks for both.

For ease of identification, these 2 belts are referred to as the primary and secondary accessory drive belts.

Additional information about the system and its operation can be found in the relevant section of the workshop manual.

Inspection and verification

1. Check the validity of the customer's complaint.

2. Visually inspect for obvious mechanical problems.

Mechanical factors

Primary drive belt condition (cracking / damage / contamination) Secondary drive belt condition (cracking / damage / contamination) Belt tension Pulley alignment coolant pump Primary tensioner assembly Air conditioning compressor Power steering pump crankshaft pulley Generator Dynamic response pump pulley Idler pulley Turbocharger Pulley Secondary tensioner assembly Coolant pump pulley

3. If an obvious cause of a problem you identified or described by the customer is found, correct it before proceeding to the next steps (if possible).

WARNING: If the engine is operated without an accessory drive belt, DTCs may be generated to prevent activation of certain components (DTC), which should be required before returning the car to the owner. The engine should not run with the belts removed for more than 2-3 minutes. Failure to follow this instruction may result in damage to the vehicle.

4. Use an approved diagnostic system or scan tool (tester), to retrieve all DTCs before referring to the Symptom Table or DTC Index (DTC).


Clear all DTCs after troubleshooting.

Symptom table

Symptom	Possible reason	Operation
Noise	Belt condition Belt tension Skewed pulleys Elements driven (including tensioners)	Check belt condition (see visual inspection). Check tensioner operation. Check pulley alignment. Check actuated elements for increased resistance to rotation. Repair if necessary.
Drive belt not holding tension	Belt condition Tensioner failure	Check belt condition (see visual inspection). Check tensioner operation. Repair if necessary.

DTC index

NOTE: Universal Scan Tools cannot read the listed codes or can only read 5-digit codes. Match the 5 digits from the scan tool with the first 5 digits of the listed 7 digit code to identify the problem (the last 2 digits give additional information read by the diagnostic system approved by the manufacturer).

NOTE: See Section 303-14 for a complete list of ECM DTCs "Electronic engine management system" in the workshop manual.

DTC	Description	Possible reason	Operation
P050600	The speed of rotation of the crankshaft, taking into account the air supply control system in idle mode, is lower than expected	Reducing the air intake capacity Accessory Drive Overload (defective/jamming element)	Check the air intake system. Check accessory drive belt and components. See the relevant section of the workshop manual.