Circuit/System Testing

WARNING: This page is about a different car, the 2007 Suzuki XL7. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, disconnect the engine coolant temperature (ECT) sensor.
Ignition ON, verify that the ECT sensor parameter is at -40°C (-40°F).
- If greater than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
CAUTION: Do NOT use a test lamp to test the continuity of the circuit. Damage to the control module may occur due to excessive current draw.

NOTE: The control module or the sensor may be damaged if the circuit is shorted to B+.
Test for less than 1 volt between the low reference circuit terminal 2 and ground.
- If greater than the specified value, test the low reference circuit for a short to B+. If the circuit tests normal, replace the ECM.
Ignition OFF, remove the fuse that supplies B+ to circuit terminal C2-56 of the ECM.
Test for less than 5 ohms between the low reference circuit terminal 2 and ground.
- If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
Install the fuse that supplies B+ to circuit terminal C2-56 of the ECM.
NOTE: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.
Ignition ON, connect a 3A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool ECT sensor parameter is greater than 142°C (288°F).
- If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
If all circuits test normal, test or replace the ECT sensor.