P1128
P1128-CLOSED LOOP FUELING NOT ACHIEVED - BANK 1
Special Tools:
For a complete wiring diagram, refer to the Wiring Information.
- When Monitored:
With the engine running.
- Set Condition:
Enable conditions are met and the O2 Sensor has not been in closed loop control at least once, the MIL illuminates and the DTC is set. Two Trip Fault. Three good trips to turn off the MIL
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
Diagnostic Test
1. ECT SENSOR OPERATION
NOTE: For this test to be valid, the thermostat must be operating correctly.
NOTE: This test works best if performed on a cold engine (cold soak).
1. Ignition on, engine not running.
2. With the scan tool, read the Engine Coolant Temperature (ECT) Sensor value. If the engine was allowed to sit overnight (cold soak), the temperature value should be a sensible value that is somewhere close to the ambient temperature.
NOTE: If engine coolant temperature is above 82°C (180°F), allow the engine to cool until 65°C (150°F) is reached.
3. Start the Engine.
4. During engine warm-up, monitor the ECT Sensor value. The temperature value change should be a smooth transition from start up to normal operating temperature 82° C (180° F). The value should reach at least 82° C (180° F).
Did the ECT value increase smoothly and did it reach at least 82°C (180°F)?
Yes
- Go To 2
No
- Verify that there is good pin to terminal contact in the ECT Sensor and Powertrain Control Module connectors. If OK, replace the Engine Coolant Temperature Sensor. Engine Coolant Temperature Sensor - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
2. ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)
1. Diagnose all other DTCs before continuing.
2. Start the engine.
3. Allow the engine to reach normal operating temperature.
4. With the scan tool, read DTCs.
NOTE: It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.
Is the DTC Active or Pending at this time?
Yes
- Go To 3
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.
3. CHECK THE O2 SENSOR VOLTAGE READINGS
NOTE: This DTC will set due to poor engine performance as well as a faulty O2 Sensor. If the vehicle exhibits any fuel system or driveability issues, or has any other driveability DTCs present, repair those concerns before proceeding with this test.
1. Turn the ignition off.
2. Disconnect the O2 Sensor 1/1 harness connector.
3. Connect the Wide-band O2 Sensor Diagnostic Connector 10367 in-line of the O2 Sensor 1/1 harness connector.
4. Start the engine and allow it to idle.
NOTE: If the Powertrain Control Module detects an active open or short on any of the O2 Sensor 1/1 circuits, it will power down all of the O2 Sensor circuits to protect the O2 Sensor PCM internal ASIC from being damaged.
5. Measure the voltage at the (K41) O2 Sensor Signal circuit and the (K902) O2 Sensor Return circuit at the Wide-band O2 Sensor Diagnostic Connector 10367 tool.
NOTE: The (K902) O2 Sensor 1/1 Return circuit voltage should read approximately 3.8 volts and the (K41) O2 Sensor 1/1 Signal circuit should read between approximately 3.35 volts and 4.25 volts if operating normally with no opens or shorts.
Do the circuit voltages read as described?
Yes
- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.
No
- Go To 4
4. CHECK THE (F343) FUSED ASD RELAY OUTPUT VOLTAGE
1. Turn the ignition off.
2. Disconnect the O2 Sensor 1/1 harness connector.
3. Remove the Wide-band O2 Sensor Diagnostic Connector 10367 tool.
4. Turn the ignition on.
5. Measure the voltage on the (F343) Fused ASD Relay Output circuit at the O2 Sensor 1/1 harness connector.
Does the voltage read battery voltage?
Yes
- Go To 6
No
- Repair the (F343) Fused ASD Relay Output circuit for an open or short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
5. CHECK THE O2 SENSOR CIRCUITS FOR A SHORT TO VOLTAGE
1. Measure for voltage at the:
- (K41) O2 Sensor 1/1 Signal circuit at the O2 Sensor 1/1 harness connector.
- (K902) O2 Sensor 1/1 Return circuit at the O2 Sensor 1/1 harness connector.
- (K89) O2 Sensor 1/1 Positive Current Control circuit at the O2 Sensor 1/1 harness connector.
Do any of the circuits measure above 0.5 volts?
Yes
- Repair the circuit that measured above 0.5 volts for a short to voltage.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 6
6. CHECK THE O2 SENSOR CIRCUITS FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the PCM C1 harness connector.
3. Measure the resistance between ground and the:
- (K41) O2 Sensor 1/1 Signal circuit at the O2 Sensor 1/1 harness connector.
- (K902) O2 Sensor 1/1 Return circuit at the O2 Sensor 1/1 harness connector.
- (K89) O2 Sensor 1/1 Positive Current Control circuit at the O2 Sensor 1/1 harness connector.
- (K79) O2 Sensor 1/1 Positive Current Control circuit at the O2 Sensor 1/1 harness connector.
Is the resistance above 10k Ohms between each of the above circuits and ground?
Yes
- Go To 7
No
- Repair the circuit that measured above below 10k Ohms for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
7. CHECK THE O2 SENSOR CIRCUITS FOR AN OPEN OR HIGH RESISTANCE
1. Measure the resistance of the:
- (K41) O2 Sensor 1/1 Signal circuit between the O2 Sensor 1/1 harness connector and the PCM C1 harness connector.
- (K902) O2 Sensor 1/1 Return circuit between the O2 Sensor 1/1 harness connector and the PCM C1 harness connector.
- (K89) O2 Sensor 1/1 Positive Current Control circuit between the O2 Sensor 1/1 harness connector and the PCM C1 harness connector.
- (K79) O2 Sensor 1/1 Positive Current Control circuit between the O2 Sensor 1/1 harness connector and the PCM C1 harness connector.
Is the resistance below 5.0 Ohms for each of the above circuits?
Yes
- Go To 8
No
- Repair the circuit that measured above 5.0 Ohms for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
8. CHECKING FUEL PRESSURE
WARNING:
The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.
1. Turn the ignition off.
2. Install Fuel Pressure Decay Tester (8978A) to the fuel rail.
3. Ignition on, engine not running.
4. With the scan tool, actuate the Fuel System test and observe the fuel pressure gauge.
NOTE: Fuel pressure specification: 400 kPa +/- 14 kPa (58 psi +/- 2 psi).
5. Turn the ignition off.
Choose a conclusion that best matches your fuel pressure reading.
Within Specification
- Go To 9
Above Specification
- Replace the fuel filter/pressure regulator. Fuel Pump Module - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
Below Specification
- Go To 14
CAUTION:
Stop All Actuations.
9. O2 SENSOR 1/1 HEATER OPERATION
1. Turn the ignition off.
NOTE: Wait a minimum of 10 minutes to allow the O2 Sensor to cool down before continuing the test. Allow the O2 Sensor voltage to stabilize at 5.0 volts.
2. Ignition on, engine not running.
3. With the scan tool, actuate the O2 Heater 1/1 Test.
4. Using the scan tool, monitor O2 Sensor 1/1 voltage for at least two minutes.
Does the voltage stay above 4.5 volts?
Yes
- Verify that there is good pin to terminal contact in the O2 Sensor 1/1 and Powertrain Control Module connectors. If OK, replace the O2 Sensor. .
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 10
10. MAP SENSOR OPERATION
1. Turn the ignition off.
2. Connect a Vacuum Gauge to a Manifold Vacuum source.
3. Start the engine.
4. Allow the engine to idle.
NOTE: If engine will not idle, maintain a constant RPM above idle.
5. Using the scan tool, read the MAP Sensor vacuum value.
Is the scan tool reading within 1" of Hg on the Vacuum Gauge reading?
Yes
- Go To 11
No
- Verify that there is good pin to terminal contact in the MAP Sensor and Powertrain Control Module connectors. If OK, replace the MAP Sensor. .
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
11. ENGINE MECHANICAL PROBLEM
1. Turn the ignition off.
2. Check for any of the following conditions/mechanical problems:
- AIR INDUCTION SYSTEM - must be free from leaks.
- ENGINE VACUUM - must be at least 13 inches in neutral
- ENGINE VALVE TIMING - must be within specifications
- ENGINE COMPRESSION - must be within specifications
- ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
- ENGINE PCV SYSTEM - must flow freely
- TORQUE CONVERTER STALL SPEED - must be within specifications
- POWER BRAKE BOOSTER - no internal vacuum leaks
- FUEL - must be free of contamination
- FUEL INJECTOR - plugged or restricted injector; control wire not connected to correct injector
Are there any engine mechanical problems?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 12
12. O2 SENSOR
1. Turn the ignition off.
2. Replace the O2 Sensor and reconnect the harness connector.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Start the engine and allow it to idle long enough for the O2 Sensor to enter closed loop operation.
6. With the scan tool, view DTCs.
Did the DTC return?
Yes
- Go To 13
No
- Repair is complete.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
13. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the related Sensors and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related Sensor and Powertrain Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Replace and program the Powertrain Control Module. .
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
14. RESTRICTED FUEL SUPPLY LINE
WARNING:
The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.
1. Turn the ignition off.
2. Raise vehicle on hoist and disconnect the fuel pressure line at the fuel pump module.
3. Install Fuel Pressure Decay Tester (8978A) between the fuel supply line and the fuel pump module.
4. Ignition on, engine not running.
5. With the scan tool, actuate the ASD Fuel System test and observe the fuel pressure gauge.
NOTE: Fuel pressure specification: 400 kPa +/- 14 kPa (58 psi +/- 2 psi).
Is the fuel pressure within specification?
Yes
- Repair or replace fuel supply line as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 15
CAUTION:
Stop All Actuations.
15. FUEL PUMP INLET STRAINER
WARNING:
The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released.
1. Turn the ignition off.
2. Remove the Fuel Pump Module and inspect the Fuel Inlet Strainer.
Is the Fuel Inlet Strainer plugged?
Yes
- Replace the Fuel Pump Inlet Strainer. Fuel Pump Module - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 16
16. FUEL PUMP MODULE
Repair
- Verify that there is good pin to terminal contact in the Fuel Pump Module, Relay and Powertrain Control Module connectors. If OK, replace the Fuel Pump Module. Fuel Pump Module - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.