P2627-O2 SENSOR 1/1 PUMP CELL CURRENT TRIM CIRCUIT LOW

For a complete wiring diagram Refer to Section 8W

When Monitored:
With the ignition on.
Set Condition:
The ECM detects a short to ground on the (K103) O2 1/1 Pump Cell Current Trim circuit for 2.0 seconds.

Possible Causes

INTERMITTENT DTC

(K103) O2 1/1 PUMP CELL CURRENT TRIM CIRCUIT SHORTED TO GROUND

(K103) O2 1/1 PUMP CELL CURRENT TRIM CIRCUIT SHORTED TO THE (K79) O2 1/1 HEATER CONTROL CIRCUIT

(K103) O2 1/1 PUMP CELL CURRENT TRIM CIRCUIT OPEN OR HIGH RESISTANCE

OXYGEN SENSOR

ENGINE CONTROL MODULE (ECM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

Diagnostic Test

1. DTC IS ACTIVE

Ignition on, engine not running.
With the scan tool, Clear DTCs in the Engine Control Module (ECM).
Start the engine.
Allow the engine to reach normal operating temperature.
Monitor the scan tool for at least two minutes.
With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

Go To 2

No

Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

2. (K103) O2 1/1 PUMP CELL CURRENT TRIM CIRCUIT SHORTED TO GROUND

Turn the ignition off.
Disconnect the Oxygen Sensor harness connector.
Disconnect the Engine Control Module (ECM) harness connector.
Measure the resistance between ground and the (K103) O2 1/1 Pump Cell Current Trim circuit in the Oxygen Sensor harness connector.

Is the resistance above 1000 ohms?

Yes

Go to 3

No

Repair the (K103) O2 1/1 Pump Cell Current Trim circuit for a short to ground.
Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

3. (K103) O2 1/1 PUMP CELL CURRENT TRIM CIRCUIT SHORTED TO THE (K79) O2 1/1 HEATER CONTROL CIRCUIT

Measure the resistance between the (K103) O2 1/1 Pump Cell Current Trim circuit and the (K79) O2 1/1 Heater Control circuit in the Oxygen Sensor harness connector.

Is the resistance above 1000 ohms?

Yes

Go to 4

No

Repair the (K103) O2 1/1 Pump Cell Current Trim circuit for a short to the (K79) O2 1/1 Heater Control circuit.
Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

4. (K103) O2 1/1 PUMP CELL CURRENT TRIM CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (K103) O2 1/1 Pump Cell Current Trim circuit between the Oxygen Sensor harness connector and the Engine Control Module (ECM) harness connector.

Is the resistance below 10.0 ohms?

Yes

Go to 5

No

Repair the (K103) O2 1/1 Pump Cell Current Trim circuit for an open circuit or high resistance.
Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

5. OXYGEN SENSOR

Turn the ignition off.
Connect the Engine Control Module (ECM) harness connector.
Replace the Oxygen Sensor in accordance with the Service Information.
Start the engine.
Allow the engine to reach normal operating temperature.
Monitor the scan tool for at least two minutes.
With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

Go to 6

No

Test Complete.
Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

6. ENGINE CONTROL MODULE (ECM)

Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Oxygen Sensor and the Engine Control Module (ECM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.
Refer to any Technical Service Bulletins that may apply.

Were any problems found?

Yes

Repair as necessary.

Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

No

Replace the Engine Control Module (ECM) in accordance with the Service Information.
Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)