Circuit/System Testing
- Ignition OFF, remove the fuse that supplies B+ to terminal C2-56 of the ECM.
- Disconnect the C-406 harness connector at the rear of the fuel tank.
- Test for less than 5.0 ohms of resistance between the low reference circuit terminal G and ground, at the ECM side of the connector.
- If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
- Install the fuse that supplies B+ to terminal C2-56 of the ECM.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal E and ground, at the ECM side of connector C-406.
- If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit/connections test normal, replace the ECM.
- If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
- Verify that the FTP Sensor parameter is less than 4.8 volts
- If greater than the specified value, test the signal circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
- At the ECM side of C-406, install a 3A fused jumper wire between the signal circuit terminal F and the 5-volt reference circuit terminal E. Verify that the FTP Sensor parameter is greater than 4.8 volts.
- If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM.
- Remove the fuel tank. Refer to REMOVAL PROCEDURE and REMOVAL PROCEDURE .
- Disconnect the FTP sensor connector
- Inspect the FTP sensor circuits in the fuel tank harness, between the FTP sensor connector and C-406 for the following conditions, and repair as necessary:
- Damaged wiring or terminals
- Open circuits
- Short to ground
- Wire to wire short
- If all circuits/connections test normal, test or replace the FTP sensor.