Cruise control – fault diagnosis
- Make
- Land Rover
- Model
- Range Rover P38 Electrical Troubleshooting Manual
- Year
- 1999 on
- Section
- Fault diagnosis › Cruise control – fault diagnosis
CRUISE CONTROL – FAULT DIAGNOSIS
TROUBLESHOOTING HINTS
5. If the interior lights operate but the cruise control switch light does not illuminate, check the bulb, B wire and RW wire. If the cruise control system operates but the cruise control switch light does not illuminate, check bulb and OW wire. 6. Inspect vacuum hoses for kinks and restrictions. 7. Inspect actuator linkage for restrictions and adjustment. 8. Check the following two input signals to the BeCM (Z238): Signal from Clutch Pedal Position Switch (X200) for vehicles equipped with a manual transmission, or the X, Y, and Z switch signals from the Gearbox Position Switch (X294) for vehicles equipped with an automatic transmission. 9. For vehicles equipped with a Petrol Engine, check the following input signal to the BeCM (Z238): Transfer box in Hi range signal from Transfer Gear Box ECU (Z256). 10. For vehicles equipped with a Diesel engine, check the Stop Lamp Switch (X168) inputs to the Engine Control Module (ECM) (Z132). 11. Note: For vehicles equipped with a manual transmission, cruise control can only be activated when the Cruise Control Switch (X115) is depressed, the transfer gear box is in Hi range (Petrol only), and the clutch pedal is not depressed. Also, the BeCM (Z238) will deactivate cruise control if the engine rpm rises above 5000 +/10 percent, due to the possibility of selecting manual without the use of the clutch (Petrol only). For vehicles equipped with an automatic transmission, cruise control can only be activated when the Cruise Control Switch (X115) is depressed, the transfer gear box is in Hi range (Petrol only), and the transmission is in one of the forward gears. The Transfer Gear Box ECU (Z256) provides the BeCM (Z238) with transfer gear box Hi range status. The Transfer Gear Box Position Switch (X294) provides the BeCM (Z238) with X, Y, Z switch status (PRND321 position information).
SYSTEM DIAGNOSIS
1. If the cruise control system does not operate correctly and the vehicle is equipped with a Petrol Engine, do Test A.
2. If the cruise control system does not operate correctly and the vehicle is equipped with a Diesel Engine, do Test E.
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