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.
Testing Procedure
To carry out tests when 40 pin connector is connected to the ECM, it is necessary to remove the two screws securing the shroud to the connector to enable the multi-meter probes to be inserted into the back of the appropriate pin. See Figure . For pin number identification, pin numbers 1, 13, 14, 27, 28 and 40 are molded onto rear of connector. See Figure . To gain access to ECM remove front seat base trim of front right seat.
- Before proceeding with testing vehicle, perform preliminary checks. See PRELIMINARY CHECKSΒ . If no problem is present, go to next step.
- If Lucas Diagnostic Equipment or Test Book cannot communicate with the ECM and engine cranks but does not start, go to next step. If scan tool other then Lucas Diagnostic Equipment or Test Book cannot communicate with ECM and engine cranks but does not start, see scan tool manufacturers procedure for checking scan tool performance. If no problem is present, check tune select resistor. See CODE 21: TUNE SELECT RESISTORΒ . If tune select resistor is okay, check engine control module power and ground circuits, see ENGINE CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in SYSTEM & COMPONENT TESTING - RANGE ROVER article.
- Check Lucas Diagnostic Equipment or Test Book connections. If connections are okay, go to next step.
- On Lucas Diagnostic Equipment check that the memory card is correct and inserted properly. On Test Book check that CD is correct and inserted properly. Check Lucas Diagnostic Equipment or Test Book internal power source. If no problem is present, check tune select resistor. See CODE 21: TUNE SELECT RESISTORΒ . If tune select resistor is okay, check engine control module power and ground circuits, see ENGINE CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in SYSTEM & COMPONENT TESTING - RANGE ROVER article.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.
