DTC P0071: Ambient Temperature Sensor Performance: Testing
NOTE:
If DTC P1492 or P1493 is also set, diagnose those DTCs first. See DTC P1492: BATTERY TEMPERATURE SENSOR VOLTAGE TOO HIGH OR DTC P1493: BATTERY TEMPERATURE SENSOR VOLTAGE TOO LOW .
- Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed and equal to zero, go to next step. If GOOD TRIP counter is not displayed and equal to zero, go to step 7.
- Turn ignition off. Disconnect BTS harness connector. BTS is located on inside of front bumper beam. Turn ignition on. Using scan tool, read ambient air temperature voltage. If voltage is more than 4.6 volts, go to next step. If voltage is 4.6 volts or less, go to step 4.
- Turn ignition off. Connect a jumper wire between BTS harness connector terminals. Turn ignition on. Using scan tool, read ambient air temperature voltage. If voltage is one volt or more, go to next step. If voltage is less than one volt, replace BTS.
- Remove jumper wire. Reconnect BTS harness connector. Start engine and let it idle. Measure voltage drop (backprobe connectors with voltmeter) of sensor ground circuit (Black/Light Blue wire) between BTS connector and terminal No. 43 at PCM C2 connector. See Fig 1. PCM is located in engine compartment, to left of air cleaner. If voltage drop is less than .1 volt, go to next step. If voltage drop is .1 volt or more, repair high resistance in sensor ground circuit.
- With engine idling, measure voltage drop (backprobe connectors with voltmeter) of signal circuit (Violet/Light Green wire) between BTS connector and terminal No. 52 at PCM C2 connector. If voltage drop is less than .1 volt, go to next step. If voltage drop is .1 volt or more, repair high resistance in signal circuit.
- If no other possible causes are remaining, replace PCM.
- Conditions that set DTC are not present at this time. Perform the following to help identify intermittent condition:
- With engine running at normal operating temperature, wiggle related wiring harness while monitoring related parameters on scan tool. If voltage changes or DTC sets while wiggling wiring harness, repair connectors or wiring harness where wiggling caused voltage to change or DTC to set.
- Review freeze frame information on scan tool. Duplicate conditions present when DTC was set.
- Refer to any technical service bulletins that may apply.
- Visually inspect related wiring harness. Check for chafed, pierced, pinched or partially broken wires.
- Visually inspect related wiring harness connectors. Check for broken, bent, pushed out or corroded terminals.
If a problem is found, repair as necessary. If no problems are found, test is complete.