Check the engine Control module (ECM) and intake air temperature (IAT) sensor connectors for contact resistance and oxidation according to Checking wiring and terminals - Intermittent Faults.
Check in particular for damage, or loose terminal pins.
Check the signal cable between engine control module (ECM) terminal 48 and intake air temperature (IAT) sensor terminal 1 for an intermittent short-circuit to Supply voltage. Remedy according to Checking wiring and terminals - Intermittent Faults and for an intermittent open-circuit Checking wiring and terminals - Intermittent Faults.
Check the ground lead between engine control module (ECM) terminal 79 and intake air temperature (IAT) sensor terminal 2 for an intermittent open-circuit. Remedy according to Checking wiring and terminals - Intermittent Faults.
Checking The Signal Cable
Ignition on
Disconnect the intake air temperature sensor connector.
Connect a voltmeter between the intake air temperature (IAT) sensor connector terminal #1 (control module side) and ground.
The voltmeter should read approximately 5 V .
Checking The Ground Lead
Connect an ohmmeter between the intake air temperature (IAT) sensor connector terminal #2 (control module side) and ground.
The ohmmeter should read approximately 0 [ohm].
Checking Wiring And Terminals
Check the cable between intake air temperature (IAT) sensor connector terminal #1 (engine control module (ECM) side) and engine control module (ECM) terminal #48. Check for a short-circuit to supply voltage according to See: Related Tests, Information and Procedures Checking Wiring and Terminals
Remedy as necessary.
Checking Wiring And Terminals
Check the cable between intake air temperature (IAT) sensor connector terminal #1 (engine control module (ECM) side) and engine control module (ECM) terminal #48. Check for an open-circuit according to Checking wiring and terminals - Permanent Faults.
Check the cable between intake air temperature (IAT) sensor connector terminal #2 (engine control module (ECM) side) and engine control module (ECM) terminal #79. Check for an open-circuit according to Checking wiring and terminals - Permanent Faults.
If all that checks out good then replace the intake temperature sensor.
SPONSORED LINKS
Monday, September 14th, 2009 AT 10:54 PM
