P0040

P0040 - 1/1 AND 2/1 O2 SENSOR HARNESS CONNECTORS REVERSED





When Monitored and Set Condition

- When Monitored: With the ignition on.
- Set Condition: At ignition on, the Powertrain Control Module (PCM) checks the voltage on the ground side of the O2 Sensor harness connector. If the voltage is higher than two volts, this DTC will set.





For a complete Powertrain Control Module Circuit Diagram, Schematics and Diagrams.

Diagnostic Test

1. PRE-DIAGNOSTIC CHECK OUT

NOTE: Always perform diagnostics with a fully charged battery.

NOTE: Check connectors - Clean/repair as necessary. Poor pin to terminal connections can set DTCs.

NOTE: Check for applicable TSBs related to the problem.

Turn the ignition on.
With the scan tool, read PCM DTCs.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Repair as necessary.
Perform this procedure prior to symptom diagnosis.

Continue

- Go To 2

2. POWERTRAIN CONTROL MODULE
Turn the ignition off.
Verify that the upstream O2 Sensors harness connectors are connected to the correct O2 Sensor and repair as necessary.
Turn the ignition on.
With the scan tool, erase all PCM DTCs.
Turn the ignition off, then back on.
Start and let the engine idle.
If the DTC does not set right away, it may be necessary to test drive the vehicle.
With the scan tool, read PCM DTCs.
Did DTC, (P0040) 1/1 AND 2/1 O2 SENSOR HARNESS CONNECTORS REVERSED, set again?

Yes

NOTE: Before continuing, verify the front O2 Sensor harness connectors are connected to the correct O2 Sensor with no damage or terminal push out. Repair as necessary.

- If OK, replace and program the Powertrain Control Module.Powertrain Control Module - Removal.
- Perform POWERTRAIN VERIFICATION TEST - VER 2. Powertrain Verification Test

No

- Go To 3

3. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.

NOTE: Check connectors - Clean/repair as necessary. Poor pin to terminal connections can set DTCs.Using the wiring diagram/schematic as a guide, inspect the wiring and connectors specific to this DTC. Wiggle the wires while checking for shorts and/or open circuits.

NOTE: Check for any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform POWERTRAIN VERIFICATION TEST - VER 2. Powertrain Verification Test

No

- The condition that caused this DTC to set is currently not present. Inspect the related wiring harness for a possible intermittent condition.