Checking Components
Check that the engine speed (RPM) sensor is correctly installed.
Check the engine speed (RPM) sensor connector. Check for intermittent contact resistance and oxidation.
HINT: The engine speed (RPM) sensor and its wiring are sensitive to interference from surrounding cables, the starter motor cable for example, or similar high amperage cables.
Interference can cause difficulty in starting the engine, prevent the engine from starting at all or cause the tachometer to flicker during start attempts etc.
Causes of interference can be:
- nearby cables, such as an incorrectly routed cable for the starter motor
- incorrectly tightened bolted joints securing the transmission to the engine.
Checking power cable
Check for incorrectly routed cables (routed too close to the engine speed (RPM) sensor).
Checking bolted joints
When removing and installing the transmission it is important that all the bolts for the engine are correctly tightened. Incorrectly tightened bolts can cause poor ground connection and interfere with the engine speed (RPM) sensor. Check that all the bolts from the transmission to the engine are correctly tightened.
Checking the wiring
Check the signal cable between the engine speed (RPM) sensor terminal #1 and engine control module (ECM) terminal #A48 (#A48) and between the engine speed (RPM) sensor terminal #2 and engine control module (ECM) terminal #A66 (#B6). Check for an intermittent short-circuit to supply voltage. Check for an intermittent short-circuit to ground. Check for an intermittent open-circuit.
Other information:
- see CHECKING WIRING AND TERMINALS
- For B5xx4T, see REPLACING THE ENGINE SPEED (RPM) SENSOR
- For B6xx4T, see ENGINE SPEED (RPM) SENSOR, REPLACING .
Remedy as necessary.
- Continue
Refer to VERIFICATION