Note. Before you troubleshoot, record all freeze data and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
Scheme 28
Scheme 29
Scheme 30
Scheme 31
Scheme 32
- Turn the ignition switch ON (II).
- Check the IAT with a scan tool or the HDS. Is about -4 °F (-20 °C) or less, or 5 V indicated? YES - Go to step 3. NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the IAT sensor and the ECM.
- Turn the ignition switch OFF.
- Disconnect the IAT sensor 2P connector.
- Connect IAT sensor 2P connector terminals No. 1 and No. 2 with a jumper wire.
- Turn the ignition switch ON (II).
- Check the IAT with a scan tool or the HDS. Is about -4 °F (-20 °C) or less, or 5 V indicated? YES - Go to step 8. NO - Replace the IAT sensor (see «SPECIAL TOOLS»(ref-221324-S23506078702006022400000) ).
- Turn the ignition switch OFF.
- Remove the jumper wire.
- Turn the ignition switch ON (II).
- Measure voltage between IAT sensor 2P connector terminal No. 2 and body ground. Is there about 5 V? YES - Go to step 13 . NO - Go to step 12.
- Measure voltage between ECM connector terminal C25 and body ground. Is there about 5 V? YES - Repair open in the wire between the ECM (C25) and the IAT sensor. NO - Substitute a known-good ECM (see «HOW TO SUBSTITUTE THE ECM FOR TESTING PURPOSES»(ref-221328-S04997151962006022400000) ) and recheck. If normal IAT is indicated, replace the original ECM (see «ECM REPLACEMENT»(ref-221329-S30667517252006022400000) ).
- Turn the ignition switch OFF.
- Disconnect ECM connector C (31P).
- Connect IAT sensor 2P connector terminal No. 1 to body ground with a jumper wire.
- Check for continuity between ECM connector terminal C18 and body ground. Is there continuity? YES - Substitute a known-good ECM (see «HOW TO SUBSTITUTE THE ECM FOR TESTING PURPOSES»(ref-221328-S04997151962006022400000) ) and recheck. If normal IAT is indicated, replace the original ECM (see «ECM REPLACEMENT»(ref-221329-S30667517252006022400000) ). NO - Repair open in the wire between the ECM (C18) and the IAT sensor.