Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

2003 Land Rover Range RoverFACTORY OEM SERVICE PROCEDURE

Engine Control Module Self Test Drive Cycle Information

Engine control module self test monitoring drive cycle information for each DTC:

P1646

Drive Cycle A

P0604

Drive Cycle A

P0605

Drive Cycle C

P0606

Drive Cycle C

NOTE: To provide compatibility with later 2005 model year DTCs, from disc 14 of the Range Rover TestBook/T4 diagnostic software, the DTCs in the following table will be displayed with new DTC numbers and descriptions. See Fig 1 .

If a standard scan tool is used then the original codes detailed above will be displayed.

Fig 1: Change To Engine Control Module Self Test DTC Display Using Disc 14 & Subsequent TestBook/T4 Software

Courtesy of LAND ROVER NORTH AMERICA, INC.

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.