Temperature Guage - Erratic Readings
NO.86/08/96/US
DATE
11/22/96
SUBJECT
Erratic Temperature Gauge Readings, Poor Grounds
MODEL
Range Rover 4.0/4.6
AFFECTED VEHICLES
LP 300191 onward
DETAIL
Loose or poor ground connections on Range Rover vehicles may cause the temperature gauge to read high or to flicker. Other electrical features may also operate incorrectly resulting in the GEMS ECU storing numerous fault codes.
The connections most likely to cause the symptoms are:
1. Engine ground
2. BeCM ground
3. Body and Engine harness ground
ACTION REQUIRED
When symptoms of a possible incomplete ground are present, follow the procedures detailed below to identify and correct the problem.
PARTS INFORMATION
RTC7769 - Anti-corrosion Wax
WARRANTY
Normal warranty policy and procedures apply
COMP. CODE
SRO
86.15.89/27 - Time: 0.20 hour.
Engine ground and engine harness ground check
85.15.89/28 - Time: 0.40 hour
BeCM ground check
PROCEDURE
Caution: Disconnect the battery before removing ground cables for cleaning and refitting.
Voltage Drop Test
1. Ensure the battery terminals are clean and secure.
2. Verify that the ground leads to the chassis and the engine block are tight.
3. Start the engine and raise the idle speed to approximately 2000 rpm to achieve maximum alternator output.
4. Switch on the windshield and rear glass electric demisters, headlights, fog lights and maximum heater blower speed.
5. Measure the voltage (mV) between the negative battery terminal and the inlet manifold.
6. If the measured voltage is greater than 130mV, stop the engine and disconnect the battery.
7. Clean, inspect and tighten the ground locations as outlined on the following pages.
8. when all grounds are cleaned and secure, connect the battery and repeat the voltage drop test to confirm that the voltage drop is now less than 130mV.
Engine Ground Cleaning and Securing
The engine ground is located behind the tensioner pulley on the accessory bracket
1. Remove and clean the main engine ground cable eyelets.
2. Verify that all surfaces are free from contamination.
3. Tighten the ground bolt securely to 6 to 7 Nm (50 to 60 in.lbs.).
BeCM Ground Cleaning and Securing
The BeCM ground is located behind the BeCM. Access and clean the BeCM ground location as follows:
1 Remove the passenger seat, and foot ventilation ducting from above the BeCM.
2. Carefully fold back the carpet to expose the grounding point.
3. Remove the ground eyelets.
4. Clean the eyelets and the area around the ground post
5. Verify that all surfaces are free from paint and contamination.
6. Tighten the ground nut securely to 6 to 7 Nm (50 to 60 in.lbs.).
Chassis Post Ground Cleaning and Securing
1. Remove and clean the main ground cable eyelets at the chassis post
2. Clean the area around the ground post
3. Verify that all surfaces are free from paint and contamination.
4. Tighten the ground bolt securely to 6 to 7 Nm (50 to 60 in.lbs.).
Main Body Ground Cleaning and Securing
NOTE: The main body ground is via the engine ground cable. This cable connects below the under-bonnet fuse box.
1. Remove and clean the main ground cable eyelets at ground connection.
2. Clean the area around the ground post
3. Verify that all surfaces are free from paint and contamination.
4. Tighten the ground nut securely to 6 to 7 Nm (50 to 60 in.lbs.).