P0601 Fault Code in Land Rover: Causes, Symptoms, and Fixes

This code indicates that the Engine Control Module (ECM/PCM) has failed its internal memory self-test. When the PCM powers up, it checks the integrity of its memory (EEPROM/ROM). If the checksum values don’t match, it triggers P0601. In simple terms → the PCM’s internal memory is corrupted or faulty.

Possible Causes

1. Faulty PCM/ECM (most common)
2. Software corruption (failed reflash, interrupted update)
3. Low battery voltage / bad alternator (voltage spikes damaging memory)
4. Wiring/grounding issues causing unstable power to the PCM
5. Moisture or heat damage inside the PCM

Symptoms

1. Check Engine Light (CEL) ON
2. Engine may stall or not start
3. Rough running or poor performance
4. Transmission shifting issues (if PCM and TCM are combined)
5. Other random electrical or module communication problems

Diagnosis & Fix

1. Clear code and retest – if it comes back immediately, PCM fault is likely.
2. Check battery and charging system – weak/unstable power supply can corrupt PCM memory.
3. Inspect PCM connectors & grounds – ensure no corrosion, loose pins, or water intrusion.
4. If wiring and power are fine →
– Reflash PCM software (dealer or specialist).
– If reflash fails → Replace PCM (and reprogram it to the vehicle’s VIN & immobilizer).