Engine Control System & Fuel System - 6.6l (Lmm) - DTC P029D to DTC p1448 Chevrolet Chevy Express H1500

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

Circuit/System Description

A fuel injector is a solenoid device, controlled by the ECM, that meters pressurized fuel to a single engine cylinder. Fuel pressure is released from above the fuel injector pintle, and is returned to the fuel tank through the fuel return lines. The difference in fuel pressure above and below the pintle causes the pintle to open. Fuel from the fuel injector tip is sprayed directly into the combustion chamber on the compression stroke of the engine. When the fuel injector delivers more fuel than needed, indicating a leaky injector, the fuel balance rates will exceed the limit bands and this DTC will set.

Conditions for Running the DTC

1. Engine has been running for more than 10 seconds.
2. Engine coolant is more than 45°C (113°F).
3. DTCs P0201-P0208, P1224, P1227, P122A, P1233, P1236, P1239, P1242, P1247, P2146, P2149, P2152 or P2155 are not set.
4. The vehicle speed is in park or neutral.
5. Engine speed is between 600-850 RPM
6. This diagnostic runs once per ignition cycle once the above criteria has been met.

Conditions for Setting the DTC

The fuel balancing rate for a cylinder is less than -7.0 mm 3 .

Action Taken When the DTC Sets

1. DTCs P029D, P02A1, P02A5, P02A9, P02AD, P02B1, P02B5 and P02B9 are Type A DTCs.
2. The control module commands the engine to operate in the Reduced Engine Power mode.
3. The message center displays Reduced Engine Power.

Conditions for Clearing the DTC

DTCs P029D, P02A1, P02A5, P02A9, P02AD, P02B1, P02B5 and P02B9 are Type A DTCs.

Diagnostic Aids

A fuel injector leak into the combustion chamber may result in mechanical damage to the cylinder.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Output Controls»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-output-controls)
3. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)

Circuit/System Verification

1. Start the engine and turn OFF all accessories.
2. Operate the vehicle within the Conditions for Running the DTC.
3. Turn OFF the engine for 60 seconds or until the ECM is powered OFF.
4. Start the engine.
5. With a scan tool, Command the Balance Rate Monitor ON. Balance rates should be between +4 mm 3 and -6.9 mm 3 in Park or Neutral. If any of the balance rates are less than -7 mm, replace the injectors for that cylinder.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Fuel Injector Replacement (Right) or Fuel Injector Replacement (Left)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

DTC P02E0

The intake air (IA) valve is a normally open valve and is only operated during a DPF regeneration. The position of the IA valve is controlled by the engine control module (ECM). The IA valve system uses a position sensor located within the valve assembly to monitor the position of the valve. The position sensor has the following circuits

1. 5-volt reference circuit
2. Low reference circuit
3. Signal circuit

The IA valve uses a motor to move the valve to a closed position and spring tension returns it to the open position. The motor has the following circuits

1. Motor control 1 circuit
2. Motor control 2 circuit

1. The ECM is powered up for more than 0.5 second.
2. The IA valve duty cycle is greater than 10 percent.
3. DTC P02E0 runs continuously.

1. The IA valve duty cycle is greater than 10 percent.
2. The IA valve control circuit is less than 25 mA.

DTC P02E0 is a Type A DTC.

DTC P02E0 is a Type A DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-output-controls)

1. Command the IA valve from 100 percent to 0 percent. The IAF Valve Commanded Position and the IAF Valve Position parameter should match.
2. After the engine has been running, turn OFF the ignition. Observe the IA Valve Position parameter fluctuates between 0 percent and 100 percent several times.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

Circuit/System Testing

1. With the ignition OFF, disconnect the ECM and the IAF valve. Test the following circuits for a short to voltage, short to ground, or open/high resistance. AI Motor Control 1 AI Motor Control 2 If a condition is found repair the affected circuit.
2. Connect the ECM. Ignition ON, and the IAF disconnected, measure for 12 volts between the following circuits and ground: AI Motor Control 1 terminal A AI Motor Control 2 terminal B If voltage is less than 12 volts on either circuit, replace the ECM. If the voltage is 12 volts on both circuits, replace the IAF valve.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup and programming.
2. «Intake Air Valve Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P02E7

The intake air (IA) valve is a normally open valve and is only operated during a DPF regeneration. The position of the IA valve is controlled by the engine control module (ECM). The IA valve system uses a position sensor located within the valve assembly to monitor the position of the valve. The position sensor has the following circuits

1. 5-volt reference circuit
2. Low reference circuit
3. Signal circuit

The IA valve uses a motor to move the valve to a closed position and spring tension returns it to the open position. The motor has the following circuits

1. Motor control 1 circuit
2. Motor control 2 circuit

1. DTCs P02E0, P02E8, P02E9, P0642 or P0643 are not set.
2. DTC P02E7 runs continuously while the IA valve is actively being controlled.

The difference between the desired IA Valve position and the actual IA Valve position is more than 3 percent for 10 seconds.

DTC P02E7 is a Type A DTC.

DTC P02E7 is a Type A DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-output-controls)

1. Command the IA valve from 100 percent to 0 percent. The IAF Valve Commanded Position and the IAF Valve Position parameter should match.
2. After the engine has been running, turn OFF the ignition. Observe the IA Valve Position parameter fluctuates between 100 percent and 0 percent several times.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

Measure the following circuits for high resistance

1. Low reference circuit
2. Signal circuit If high resistance is found, repair the affected circuit. If no resistance is found, replace the IA valve.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. Refer to «Control Module References»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup and programming.
2. «Intake Air Valve Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

DTC P02E8 or P02E9

The intake air (IA) valve is a normally open valve and is only operated during a DPF regeneration. The position of the IA valve is controlled by the engine control module (ECM). The IAF Valve system uses a position sensor located within the valve assembly to monitor the position of the valve. The position sensor has the following circuits

1. 5-volt reference circuit
2. Low reference circuit
3. Signal circuit

The IAF valve uses a motor to move the valve to a closed position and spring tension returns it to the open position. The motor has the following circuits

1. Motor control 1 circuit
2. Motor control 2 circuit

P02E8 and P02E9

1. DTCs P0698 or P0699 are not set.
2. The ignition is ON.
3. DTCs P02E8 and P02E9 run continuously.

P02E8

The IAF valve position is more than 0.102 volt for 3 seconds.

P02E9

The IAF valve position is less than 4.75 volts for 3 seconds.

DTCs P02E8 and P02E9 are Type A DTCs.

DTCs P02E8 and P02E9 are Type A DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-output-controls)

1. Command the IA valve from 100 percent to 0 percent. The IAF Valve Commanded Position and the IAF Valve Position parameter should match.
2. After the engine has been running, turn OFF the ignition. Observe the IA Valve Position parameter fluctuates between 100 percent and 0 percent several times.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

1. Ignition OFF, disconnect the harness connector at the IA valve. Allow up to 2 minutes for the ECM to completely power down.
2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal C and ground. If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, test for 4.8-5.2 volts between 5-volt reference circuit terminal F and ground. If less than 4.8 volts, test 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Verify the scan tool IAF valve position voltage is less than 0.1 volt. If greater than 0.1 volt, test the signal circuit terminal E for a short to voltage. If the circuit tests normal, replace the ECM.
5. Install a 3A fused jumper wire between the signal circuit terminal E and the 5-volt reference circuit terminal F of the IA valve harness connector. Verify that the voltage is more than 4.8 volt. If less than 4.8 volt, test the IA valve signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
6. If all circuits test normal, replace the IA valve.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. Refer to «Control Module References»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup and programming.
2. «Intake Air Valve Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) monitors changes in crankshaft speed using input from the crankshaft position sensor. The ECM adjusts the fuel delivery to each cylinder in order to minimize crankshaft speed changes. If the ECM identifies a cylinder or cylinders requiring an excessive amount of fuel in order to maintain the correct crankshaft speed, a DTC will set.

P0300

1. The engine is running at idle for more than 10 seconds.
2. The engine coolant temperature (ECT) is more than 40°C (104°F).
3. DTC P0300 runs once per ignition cycle when the above conditions are met.
4. DTCs P0301-P0308 must run before DTC P0300 runs.

P0301-P0308

1. DTCs P0117, P0118, P0335, P0336, P0502, P2146, P2149, P2152, P2155 and P062C are not set.
2. The ECT is more than 40°C (104°F).
3. The engine is running at idle for more than 10 seconds.
4. The engine RPM is between 500-1,500 RPM.
5. The vehicle speed is less than 3 mph.
6. The calculated fuel rate is between 3 mm 3 and 25 mm 3 .
7. DTCs P0301-P0308 will run once per ignition cycle in a total of 440 engine revolutions when the above conditions are met.

Cylinder RPM is less than the minimum average cylinder speed after an injection event counted 180 times.

Actions Taken When the DTC Sets

DTCs P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, and P0308 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, and P0308 are Type B DTCs.

Schematic Reference

Engine Controls Connector End Views

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Unplug the fuel injector for the cylinder that indicated the misfire.
2. Start the engine. Record the DTCs that set. The appropriate injector control circuit DTC P0201-P0208 should set. If the appropriate injector control circuit DTC did not set replace the ECM.
3. Reconnect the injector and clear the DTCs. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List. If any DTCs other than P0300-P0308 are set, diagnose those DTCs first. If only DTC P0300-P0308 are set, go to «Fuel Injector Balance Test with Tech 2»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-troubleshooting-diagnosis) .

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

DTC P0335 or P0336

Typical Scan Tool Data

CKP Sensor Signal Present

The hall effect crankshaft position (CKP) sensor signal indicates the crankshaft speed and position. There are 57 teeth on the front of the crankshaft sprocket, plus a sync gap. The CKP sensor will output an ON/OFF pulse as each window passes the sensing element. The CKP sensor is connected directly to the engine control module (ECM) by the following circuits

1. The 5-volt reference circuit
2. The low reference circuit
3. The signal circuit

P0335

1. The engine is cranking or running.
2. The camshaft position (CMP) sensor signal is present.
3. DTC P0335 runs continuously when the above conditions are met.
4. DTCs P0652 or P0653 are not set.

P0336

1. The engine is cranking or running.
2. DTC P0336 runs continuously when the above condition is met.
3. DTCs P0652 or P0653 are not set.

P0335

The ECM determines no signal from the CKP sensor for less than 8 seconds.

P0336

The ECM determines that the CKP sensor signal is out of range for less than 2 seconds.

DTCs P0335 and P0336 are Type A DTCs.

DTCs P0335 and P0336 are Type A DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)

1. If DTCs P0642 or P0643 are set, diagnose those DTCs first.
2. The engine starts and runs.
3. Engine running, observe the DTC information with a scan tool. DTCs P0335 or P0336 should not set.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

P0335

1. Disconnect the CKP sensor.
2. Test for less than 1 ohm of resistance between low reference circuit terminal 2 on the ECM side of the connector and ground. If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 3 on the ECM side of the connector and ground. If less than the specified range, test the 5-volt reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal 2 on the ECM side of the connector and ground. If less than the specified range, test the affected signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM. If greater than the specified range, test the affected signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
5. Ignition OFF, connect a fused jumper wire connected to the CKP signal circuit terminal 2 on the ECM side of the connector.
6. Ignition ON, momentarily touch the end of the fused jumper wire to ground. The crank signal present and the engine RPM parameters on the scan tool should charge. If the crank signal present and the engine RPM does not change, replace the ECM.
7. Ignition OFF, inspect the wiring harness for any damage, opens, or shorts. If the circuits test normal replace the CKP sensor.

P0336

1. Ensure that the CKP sensor circuits are not routed too closely to the fuel injector wiring after-market add-on electrical equipment, solenoids, relays or motors.
2. Ignition OFF, inspect the CKP sensor for correct installation. If the sensor is loose, inspect the sensor and the O-ring for damage, replace as necessary.
3. Inspect the engine for the following conditions: The engine oil for debris The crankshaft reluctor wheel for damage or foreign material passing between the sensor and reluctor wheel The timing chain, tensioner, and sprockets for wear or damage
4. If no other condition is found, replace the CKP sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Crankshaft Position Sensor Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Control Module References»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
3. «Crankshaft Reluctor and Oil Pump Drive Gear Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-2-of-5)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

DTC P0340 or P0341

Cam Signal Present

The hall effect camshaft position (CMP) sensor produces 3 ON/OFF pulses for each revolution of the camshaft. The CMP output is pulse width encoded. The engine control module (ECM) uses the CMP and crankshaft position (CKP) output pulses to determine the engine speed and position. The CMP is connected directly to the ECM by the following circuits

1. The 5-volt reference circuit
2. The low reference circuit
3. The CMP sensor signal circuit

P0340

1. The ignition is ON.
2. The engine is turning faster than 50 RPM.
3. DTCs P0340 and P0341 run continuously when the above conditions are met.
4. DTCs P0335, P0336, P0642, or P0643 are not set.

P0341

1. The ignition is ON.
2. The engine is turning faster than 50 RPM.
3. DTCs P0340 and P0341 run continuously when the above conditions are met.

P0340

The ECM does not see a CMP sensor signal for more than 2 seconds.

P0341

The ECM determines that the CMP sensor signal is out of range for less than 2 seconds.

DTCs P0341 and P0342 are Type A DTCs.

DTCs P0341 and P0342 are Type A DTCs.

If the CMP sensor signal is lost while running, the engine will operate normally. If the CMP sensor signal is not present on start-up, the engine will not start.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)

1. If DTCs P0642 or P0643 are set, diagnose those DTCs first.
2. Engine running, observe the DTC information with a scan tool. DTCs P0340 or P0341 should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

1. Ensure that the CMP sensor circuits are not routed too closely to the fuel injector wiring, after-market add-on electrical equipment, solenoids, relays, or motors.
2. With the key ON and the CMP sensor disconnected, measure the voltage between the 5-volt reference terminal 3 and a good ground and observe that the DMM measures 4.98-5.02 volts. If the DMM does not measure 4.98-5.02 volts, test the 5-volt reference for an open or high resistance. If the circuits test normal, replace the control module.
3. With the key ON and the CMP sensor disconnected, measure the voltage between the 5-volt reference circuit terminal 3 and the low reference circuit terminal 2 and observe that the DMM measures 4.98-5.02 volts. If the DMM does not measure 4.98-5.02 volts, test the low reference for an open or high resistance. If the circuits test normal, replace the control module.
4. With the key ON and the CMP sensor disconnected, connect a fused jumper wire to the signal circuit terminal 1 and momentarily and repeatedly probe the low reference circuit terminal 2, and observe if the Cam Signal Present and Engine RPM parameters change. If the cam signal and Engine RPM parameters do not change, test the signal circuit for an open, high resistance, a short to ground, a short to voltage. If the circuits test normal, replace the control module.
5. Remove the front engine cover and inspect the CMP sensor for physical damage, loose or improper installation, excessive air gap, foreign material passing between the sensor and the reluctor wheel, timing gear misalignment, or front engine cover damage.
6. Inspect the CMP reluctor wheel for physical damage, improper installation, or excessive endplay or looseness.
7. If no other condition is found, replace the CMP sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Camshaft Position Sensor Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Control Module References»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
3. «Camshaft Reluctor Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-2-of-5)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) tests the exhaust gas recirculation (EGR) flow when the EGR is in operation. EGR desired flow is compared to EGR actual flow. If EGR flow is lower or higher than expected DTC P0401 or P0402 will set.

1. DTCs P0101, P0102, P0103, P0403, P0405, P0406, P046C are not set.
2. The engine is running
3. The EGR valve is actively being controlled.
4. DTCs P0401 and P0402 run continuously when the above conditions are met.

P0401

The ECM calculated air flow deviation based on the MAF sensor input during EGR operation indicates insufficient EGR flow for 15 seconds.

P0402

The ECM calculated air flow deviation based on the MAF sensor input during EGR operation indicates excessive EGR flow for 15 seconds.

DTCs P0401 is a Type B DTC.

DTC P0402 is a Type A DTC.

DTCs P0401 is a Type B DTC.

DTC P0402 is a Type A DTC.

Inspect for the following conditions that may cause this DTC to set

1. Contamination on the MAF sensor element
2. Restriction before or after the MAF
3. Skewed MAF sensor

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)

1. If DTC P0101, P0403, P0405, P0406, P046C, P0698, or P0699 are set, diagnose these DTCs.
2. Using the output controls on the scan tool command the EGR solenoid to 10 percent. If the actual EGR position remains stationary, replace the EGR valve.
3. Inspect the exhaust system for leaks, restrictions, or for modification of the original equipment manufacture (OEM) part.
4. Visually inspect for leaks between the MAF sensor and the turbocharger.
5. Visually inspect for a restriction in the air cleaner or the air intake ducts.
6. Visually inspect for a restriction in the turbocharger charge air cooler.
7. Visually inspect for a restriction in the intake manifold.
8. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

Inspect the charge air cooler for leaks. Refer to Charge Air Cooler Diagnosis (Charge Air Cooler Air Leak Test) Charge Air Cooler Diagnosis (Full System Air Leak Test) .

1. If no problem is found, perform the component testing.

Component Testing

1. Using the output controls on the scan tool command the EGR solenoid to 10 percent. If the actual EGR position remains stationary, replace the EGR valve.
2. Spray the EGR valve gaskets and EGR cooler gaskets with a soap solution. Start the engine. Command the turbocharger vane position control solenoid ON to 100 percent and inspect for leaks around the EGR valve gaskets. If a leak is found replace the EGR valve gasket.
3. Remove the EGR valve. Refer to «Exhaust Gas Recirculation Valve Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2) and inspect that the EGR is not stuck, that there are no leaks or restrictions in the EGR valve and EGR passages, and that there is no debris or damage that can cause the EGR valve to stick partially open or partially closed. If the EGR valve is sticking, or is damaged, replace the EGR valve.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Exhaust Gas Recirculation Valve Replacement

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0403 or P046C

EGR Position Sensor

The engine control module (ECM) uses the exhaust gas recirculation (EGR) position sensor to determine the position of the EGR valve. The ECM sends a reference voltage through the 5-volt reference circuit to the EGR position sensor. The ECM provides a voltage return path for the sensor through the low reference circuit. A variable voltage signal, based on the EGR valve position, is sent from the sensor to the ECM through the EGR position sensor signal circuit. The ECM compares the actual EGR position with the desired EGR position when the EGR valve is commanded open or closed.

The EGR valve is controlled by the ECM through the EGR motor high control and the EGR motor low control circuits. The ECM supplies voltage that is near ignition voltage to the high and low control circuits at all times. The ECM will pulse width modulation (PWM) the low control circuit to ground when EGR is desired. The lower the pulse width, the more the valve will open. The ECM will PWM the high control circuit to ground when the EGR valve is desired closed.

P0403

1. The engine is running for more than 0.5 second.
2. The EGR duty cycle is more than 10 percent.
3. DTC P0403 runs continuously when the above conditions are met.

P046C

1. DTCs P0401, P0402, P0403, P0642, or P0643 are not set.
2. The EGR valve is actively being controlled.
3. DTC P046C runs continuously when the above conditions have been met.

P0403

1. The ECM detects an electrical malfunction on an EGR motor control circuit.
2. The above condition is present for more than 30 seconds.

P046C

1. The difference between the actual EGR position and the desired EGR position is more than 3 percent.
2. The above condition is present for more than 5 seconds.

DTCs P0403 and P046C are Type B DTCs.

DTCs P0403 and P046C are Type B DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-output-controls)

Special Tools

EN-48565 EGR Test Harness

1. Command the EGR valve to 30 percent with a scan tool. The commanded EGR position and the Actual EGR position should match.
2. Engine running, observe the DTC information with a scan tool. DTCs P0403 or P046C should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

1. Turn OFF the ignition. Disconnect the EGR valve. Install the EN-48565 between the EGR valve and the harness connector.
2. Turn ON the ignition. Command the EGR valve to 50 percent and back to 0 percent. The EGR test harness lamp should turn ON between 10 percent and 50 percent, and turn OFF at 0 percent. If the lamp does not turn ON and OFF, test both motor control circuits for an open/high resistance, short to voltage, or short to ground. If the circuits test normal, replace the control module. If the lamp turns ON and OFF, replace the EGR valve.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Exhaust Gas Recirculation Valve Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Control Module References»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

DTC P0405 or P0406

EGR Position Sensor

The engine control module (ECM) uses the exhaust gas recirculation (EGR) position sensor to determine the position of the EGR valve. The ECM sends a reference voltage through the 5-volt reference circuit to the EGR position sensor. The ECM provides a voltage return path for the sensor through the low reference circuit. A variable voltage signal, based on the EGR valve position, is sent from the sensor to the ECM through the EGR position sensor signal circuit. If the ECM detects an EGR position sensor voltage that is less than or more than the normal operating range, DTC P0405 or P0406 sets.

1. DTCs P0698 and P0699 are not set.
2. The ignition is ON.
3. This DTC runs continuously when the above conditions are met.

P0405

The EGR position sensor voltage is less than 0.26 volt for more than 3 seconds.

P0406

The EGR position sensor voltage is more than 4.75 volt for more than 3 seconds.

DTCs P0405 and P0406 are Type B DTCs.

DTCs P0405 and P0406 are Type B DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)

1. The EGR Position Sensor parameter is between 0.25-4.75 volts.
2. Engine running, observe the DTC information with a scan tool. DTCs P0405 or P0406 should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

1. Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit terminal B and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
2. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal A and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
3. Ignition ON, and the EGR valve disconnected, observe that the EGR Position parameter on the scan tool is 0 volt. If the EGR Position parameter is more than 0 volt, test the signal circuit for a short to voltage. If the circuits test normal, replace the ECM.
4. Ignition ON and the EGR valve disconnected, connect a jumper wire between the 5-volt reference circuit terminal A of the EGR valve and the signal circuit terminal C of the EGR valve and observe with a scan tool that the EGR sensor parameter displays 4.98-5.02 volts. If the EGR Sensor parameter is less than 4.98 volts, test the signal circuit for an open, short to ground, or high resistance. If the circuits test normal, replace the control module.
5. If the circuits, test normal replace the EGR valve.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Exhaust Gas Recirculation Valve Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Control Module References»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

The diesel oxidation catalyst (DOC), main function is to control emissions of Non Methane Hydro Carbons (NMHC). The secondary function of the DOC is to assist with the diesel particulate filter (DPF) regeneration, by obtaining and sustaining the temperature necessary for regeneration. The engine control module (ECM) monitors the exhaust gas temperature (EGT) sensor 1 to determine if the operating temperature of the catalyst is achieved during a regeneration event.

When the ECM detects that the DOC is not reaching a pre-determined temperature during an active regeneration event this DTC runs and fails.

1. The engine control module (ECM) must be commanding an active regeneration.
2. DTC P0420 runs once during an active regeneration event.

1. The ECM determines that the DOC functionality has degraded below a calibrated threshold, during a regeneration event.
2. The condition exists for greater than 4 minutes.

1. DTC P0420 is a type B DTC.
2. DPF regeneration will be inhibited.

DTC P0420 is a type B DTC.

The use of Off Road Red Dye Fuel or non ultra low sulfur fuel the vehicle may be a possible contributor to this DOC failure.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Component Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
3. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Description and Operation

Diesel Particulate Filter (DPF) System Description

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-output-controls)

1. Verify that DTCs P003A, P0047, P0048, P0101, P0201-P0208, P02A1, P02A5, P02A9, P02AD, P02B1, P02B5, P02B9, P02E0, P02E7-P02E9, P029D, P0300-P0308, P0402, P046C, P0545, P0546, P2032, P2033 are not set. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) .
2. Verify that exhaust leaks do not exist before the DOC. Refer to «Exhaust Leakage»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system__exhaust-leakage) .
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freez Frame/Failure Records data.

1. Inspect for the following conditions, which may cause a diesel oxidation converter (DOC) to degrade: Off Road Fuel or Red Dye Fuel Low quality B-20 fuel Fuel Containing high sulfur content Engine oil or coolant consumption
2. Inspect the DOC for the following conditions: Physical damage or alterations Internal rattles caused by a damaged catalyst substrate If a condition is found, replace the DOC.
3. If all engine and exhaust system test are normal, replace the DOC.

Note. After performing the system repair, perform the following: A code clear with a scan tool, regardless of whether or not a DTC is set A Diesel Particulate Filter (DPF) Service Regeneration with a scan tool Perform the above in order to remove soot from the DPF and avoid possible DPF failure.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Exhaust Particulate Filter Cleaning (DPF Service Regeneration)»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Particulate Filter Cleaning (DPF Regeneration Enable)»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system)
2. «Catalytic Converter Replacement (Dual Exhaust - Left)»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system) or «Catalytic Converter Replacement (Dual Exhaust - Right)»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system) or «Catalytic Converter Replacement (Single Exhaust - 4.3L, 4.8L and 5.3L)»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system) or «Catalytic Converter Replacement (6.6L (LBZ/LLY))»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system) or «Catalytic Converter Replacement (6.6L (LMM))»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system)
3. «Exhaust Particulate Filter Cleaning (DPF Service Regeneration)»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Particulate Filter Cleaning (DPF Regeneration Enable)»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system) for Service Regeneration

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

The engine control module (ECM) adjusts the fuel delivery in order to control crankshaft speed at idle. The ECM monitors the engine speed and will detect an out of range idle speed for the amount of fuel that is delivered.

1. DTCs P0016, P0117, P0118, P0335, or P0336 are not set.
2. The engine is running at idle.
3. The engine coolant temperature (ECT) is more than 50°C (122°F).
4. The accelerator pedal position (APP) angle is 0 percent.
5. These DTCs run continuously.

P0506

The ECM detects the actual idle speed is at least 100 RPM below the desired idle speed for greater than 19 seconds.

P0507

The ECM detects the actual idle speed is at least 200 RPM above the desired idle speed for greater than 19 seconds.

DTCs P0506 and P0507 are Type B DTCs.

DTCs P0506 and P0507 are Type B DTCs.

Inspect for any of the following conditions

1. A crankcase overfill can cause oil to be forced through the positive crankcase ventilation (PCV) system.
2. An outside source that has allowed oil or fuel to enter the air induction system.
3. An aftermarket performance kit using an external fuel source.

Schematic Reference

Engine Controls Schematics

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-output-controls)

1. Engine running, compare the scan tool Desired Idle Speed parameter to the Engine Speed parameter. Both engine speed parameters should be within 50 RPM of each other.
2. Elevate the engine speed in 25 RPM increments to 1,300 RPM using a scan tool. With each commanded increment, the actual Engine Speed parameter should stay within 25 RPM of the commanded speed. If the vehicle passes the Circuit/System Verification Test, operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records list.
3. Engine running, observe the DTC information with a scan tool. DTCs P0506 or P0506 should not set.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

1. If there are any other DTCs set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) .
2. Attempt to start the engine. If the engine does not start refer to «Engine Cranks but Does Not Run»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-troubleshooting-diagnosis) .
3. Inspect for mechanical conditions that can limit engine speed. If any abnormal conditions are present, refer to «Symptoms - Engine Mechanical»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-1-of-5) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

DTC P0545 or P0546

EGT Sensor 1

The exhaust gas temperature sensors position 1 are variable resistors that measures the temperature of the exhaust at the inlet second outlet of the diesel particulate filter (DPF). The engine control module (ECM) supplies a bias 5-volt signal to the EGT signal circuit, and supplies a ground to the low reference circuit. When the EGT is cold, the sensor resistance is low. When the EGT temperature increases, the sensor resistance increases. With high sensor resistance, the ECM detects a higher voltage on the EGT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the EGT signal circuit.

1. The ignition is ON.
2. This DTC runs continuously when the above condition is met.

P0545

1. The ECM detects that the EGT sensor is less than 0.32 volt.
2. The condition exists for greater than 1 second.

P0546

The ECM detects that the exhaust temperature sensor is greater than 3.37 volts for greater than 1 second.

1. DTCs P0545 and P0546 are Type A DTCs.
2. Normal regeneration will be inhibited.

DTCs P0545 and P0546 are Type A DTCs.

1. Inspect the EGT sensor terminals for corrosion.
2. Measure and record the resistance of the EGT sensor at various ambient temperatures greater than -8°C (+18°F), then compare those measurements to the «Temperature Versus Resistance (Exhaust Gas Temperature Sensor)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2__temperature-versus-resistance-exhaust-gas-temperature) «Temperature Versus Resistance (Fuel Temperature Sensor)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-2-of-2__temperature-versus-resistance-fuel-temperature-sensor) or «Temperature Versus Resistance (IAT Sensor 1)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-2-of-2__temperature-versus-resistance-iat-sensor-1) or «Temperature Versus Resistance (ECT Sensors)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-2-of-2__temperature-versus-resistance-ect-sensors) or «Temperature Versus Resistance (IAT Sensor 2)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-2-of-2__temperature-versus-resistance-iat-sensor-2) .
3. A short to a separate 5-volt source occurs, this DTC will set.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
3. «Engine Controls Component Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Description and Operation

Diesel Particulate Filter (DPF) System Description

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)

1. Engine running, observe the scan tool EGT Sensor 1 parameter. The reading should be within the normal range -39°C to +999°C (-38°F to +1,830°F), depending on the current ambient temperature and the vehicle operating conditions.
2. Engine running, observe the DTC information with a scan tool. DTCs P0545 or P0546 should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

1. Ignition OFF, disconnect the harness connector at the EGT sensor 1.
2. Ignition OFF, for 90 seconds. Test for less than 5 ohms of resistance between the low reference circuit terminal A and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, verify the scan tool EGT Sensor 1 parameter is greater than 998°C (1,828°F). If less than the specified range, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the ECM.
4. Install a 3A fused jumper wire between the signal circuit terminal A and a good ground. Verify the scan tool EGT parameter is less than -39°C (-38°F). If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If all circuits test normal, test the sensor.

Measure and record the resistance of the EGT sensor 1 at various ambient temperatures and compare those measurements to the Temperature Versus Resistance (Exhaust Gas Temperature Sensor) Temperature Versus Resistance (Fuel Temperature Sensor) or Temperature Versus Resistance (IAT Sensor 1) or Temperature Versus Resistance (ECT Sensors) or Temperature Versus Resistance (IAT Sensor 2) .

Note. After performing the system repair, perform the following

1. A code clear with a scan tool, regardless of whether or not a DTC is set
2. A Diesel Particulate Filter (DPF) Regeneration Enable with a scan tool

Perform the above to avoid possible soot overloading conditions or possible damage to the DPF.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Exhaust Particulate Filter Cleaning (DPF Service Regeneration)»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Particulate Filter Cleaning (DPF Regeneration Enable)»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system) for Regeneration Enable
2. «Exhaust Temperature Sensor Replacement - Position 1»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
3. «Engine Control Module Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2__engine-control-module-replacement)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

Description

These DTCs apply to internal microprocessor integrity conditions within the engine control module (ECM). This diagnostic also addresses if the ECM is not programmed.

The ECM monitors its ability to read and write to the memory. It also monitors a timing function.

P0602

1. The ignition switch is ON.
2. The controller is identified as a service replacement ECM.

P0606

1. The ignition switch is in Run or Crank.
2. The power take-off (PTO) is inactive.
3. The cruise control is inactive.

P060B

1. The engine speed is more than 650 RPM.
2. The ECM is powered up.

P061C

1. The ignition is ON.
2. The engine speed is less than 1,300 RPM.

P062C

The ignition is ON.

P062F

The ignition is ON.

P2610

The ECM is powered up.

P0602

1. The ECM has not been programmed at Key On and Engine Off for 0.1 second.
2. This diagnostic runs continuously.

P0606

1. The ECM detects a microprocessor undervoltage or overvoltage condition. OR
2. The ECM detects an internal bus communication error. OR
3. The ECM detects an internal clock error. OR
4. The ECM detects an internal injector control error.
5. All tests run in less than 1 second.
6. This DTC runs continuously.

P060B

1. The ECM detects an incorrect internal analog/digital (A/D) signal for less than 1 second.
2. This DTC runs continuously.

P061C

1. The ECM detects that there is a difference between the CKP engine speed and the calculated engine speed of more than 320 RPM for less than 1 second.
2. This diagnostic runs continuously.

P062C

1. The ECM detects a fault in the ship that calculates redundant vehicle speed for more than 1 second.
2. This DTC runs continuously.

P062F

1. The ECM did not complete the last electronic erasable programmable read only memory (EEPROM) write event during the last ECM power down.
2. This diagnostic runs once per ignition cycle at power up.

P2610

1. The ignition off-timer is less than 0 second. OR
2. The ignition off-timer is less than 5 seconds for more than 10 seconds. OR
3. The ignition off-timer is unchanged for 60 seconds. OR
4. The ignition off-timer is not incrementing in 1-second intervals.

1. DTCs P0602, P0606, P060B, P061C, P062C and P062F are Type A DTCs.
2. DTC P2610 is a Type B DTC.

1. DTCs P0602, P0606, P060B, P061C, P062C and P062F are Type A DTCs.
2. DTC P2610 is a Type B DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Observe the DTCs with the scan tool. If DTC P0602 or P062F is set, attempt to program the ECM before replacing the ECM. Refer to «Service Programming System (SPS)»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__service-programming-system-sps) . If DTC P0606 was set while performing SPS Programming, clear the DTCs and exit the diagnostic. If DTC P0606 was set with DTC P0851 or P0852, first go to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) .
2. Test the voltage and ground circuits to the control module for the following: A short An open High resistance
3. If DTC P2610 is set, turn the ignition OFF and then completely disconnect the ECM harness connector from the ECM for approximately 1 minute. Reinstall all of the ECM connectors and then attempt to clear codes with the scan tool. If DTC P2610 resets after code clear, replace the ECM.
4. Replace the ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0640

The intake air (IA) heater is located in the air inlet tube and is used to warm the incoming air to aid in starting the engine and for proper cylinder combustion. The glow plug control module (GPCM) will command the IA heater ON when the engine coolant temperature is below 40°C (104°F). The power to the IA heater is supplied by the battery positive voltage circuit. The IA heater is connected to the GPCM by the following circuits

1. The IA heater temperature signal circuit
2. The IA heater command 1 circuit
3. The IA heater command 2 circuit
4. The IA heater voltage signal circuit
5. The IA heater current signal circuit
6. The IA heater feedback signal circuit

If there is a fault on any of these circuits, a DTC will set.

1. The IA heater is commanded OFF.
2. DTC P0640 runs continuously when the above condition is met.

The digital response signal is high and the command 2 signal is activated.

DTC P0640 is a Type B DTC.

DTC P0640 is a Type B DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)

1. Ensure that the IA heater Command 1 CKT Short to Voltage parameter displays NO.
2. Ensure that the IA heater can be commanded ON.
3. Engine running, observe the DTC information with a scan tool. DTC P0640 should not set.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

1. Disconnect the IA heater
2. Turn ON the ignition. Test the IA heater command 1 circuit terminal 2 for less than 12 volts. If greater than 12 volts, test the command 1 circuit for a short to voltage. If the circuit tests normal, replace the glow plug control module.
3. If the command 1 circuit tests normal, replace the IA heater.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for GPCM replacement, setup, and programming
2. «Intake Air Heater Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0642 or P0643

The engine control module (ECM) supplies 5 volts to components through 5-volt reference circuits. These 5-volt reference circuits are independent of each other outside the ECM, but are bussed together in three reference groups inside the ECM. Therefore, a circuit condition on one sensor 5-volt reference circuit may affect multiple components. The ECM monitors voltage on the 5-volt reference circuits.

1. The ignition is ON.
2. The diagnostics run continuously.

P0642

1. The ECM detects the 5-volt reference 1 circuit voltage is less than 4.7 volts.
2. The above condition is present for 2 seconds.

P0643

1. The ECM detects the 5-volt reference 1 circuit voltage is more than 5.2 volts.
2. The above condition is present for 2 seconds.

DTC P0642 and P0643 are Type A DTCs.

DTC P0642 and P0643 are Type A DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Output Controls»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-output-controls)
3. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)

1. The engine starts and runs.
2. Observe the 5-Volt Reference 1 Circuit Status parameter with a scan tool. The parameter should display OK.
3. Engine running, observe the DTC information with a scan tool. DTCs P0642 or P0643 should not set.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

1. Turn OFF the ignition for 30 seconds or until the ECM powers down.
2. Disconnect the camshaft position (CMP) sensor.
3. Turn ON the ignition, with engine OFF and measure the voltage from the 5-volt reference circuit of the CMP sensor to a good ground with a DMM. If the voltage measures 4.7-5.2 volts, replace the camshaft position sensor.
4. With the DMM still connected to the 5-volt reference circuit, disconnect the crankshaft position (CKP) sensor. If the voltage measures 4.7-5.2 volts, replace the CKP sensor.
5. Test the 5-volt reference 1 circuits for a short to ground or a short to voltage. If no problem was found in the 5-volt reference circuit, replace the ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Camshaft Position Sensor Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Crankshaft Position Sensor Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
3. «Control Module References»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P064C

Ignition 1 Signal

The glow plug control module (GPCM) has the ability to perform internal diagnostics for voltage and output state of the glow plugs. The GPCM will send a message to the engine control module (ECM) to set this DTC.

1. The ignition is ON.
2. DTC P064C runs continuously.

The GPCM detects a variation between the main battery supply to the GPCM and battery supply to the ECM, or an internal condition for 3 second.

DTC P064C is a Type B DTC.

DTC P064C is a Type B DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)

1. If you cannot duplicate the conditions, refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor) .
2. Engine running, observe the DTC information with a scan tool. DTC P064C should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

Monitor the GPCM Data Display Ignition 1 Signal parameter for battery voltage with a scan tool.

1. If the Ignition 1 Signal parameter is not battery voltage, test the battery positive voltage circuit to the glow plug control module for an open, or short to ground. If the circuits test normal replace the GPCM.
2. If the Ignition 1 Signal parameter is battery voltage, replace the GPCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for GPCM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

DTC P0650

The malfunction indicator lamp (MIL) is located on the instrument panel cluster (IPC). The MIL informs the driver that an emission system fault has occurred and that the engine control system requires service. The engine control module (ECM) performs a self test for the MIL lamp and its circuitry by commanding the MIL ON and OFF every time the engine is started. The ECM monitors the MIL control circuit for conditions that are incorrect for the commanded states of the MIL.

1. The ignition is ON.
2. DTC P0650 runs continuously.

The control module detects that the commanded state of the malfunction indicator lamp (MIL) driver and the actual state of the MIL control circuit do not match for greater than 3 seconds.

DTC P0650 is a Type A DTC

DTC P0650 is a Type A DTC

Schematic Reference

1. «Engine Controls Schematics»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Instrument Cluster Schematics»(/chevrolet/chevy-express-h1500/2003-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
3. «Engine Controls Component Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
4. «Displays and Gages Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
5. «Displays and Gages Component Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-output-controls)

An intermittent or poor connection at the MIL control circuit in the inline harness connector may cause this DTC to set. Inspect the connector terminals for any condition that may result in excessive resistance. Refer to Testing for Intermittent Conditions and Poor Connections .

1. Ignition ON, command the MIL ON and OFF with a scan tool. Observe the MIL is should turn ON and OFF with each command.
2. Engine running, observe the DTC information with a scan tool. DTC P0650 should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

1. Ignition OFF, disconnect the harness connector at the IPC.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, replace the IPC.
3. Connect a test lamp between the control circuit and the ignition circuit.
4. Command the MIL ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If all circuits test normal, replace the IPC.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM and ICM replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0652 or P0653

The engine control module (ECM) supplies 5 volts to components through 5-volt reference circuits. These 5-volt reference circuits are independent of each other outside the ECM, but are bussed together in three reference groups inside the ECM. Therefore, a circuit condition on one sensor 5-volt reference circuit may affect multiple components. The ECM monitors voltage on the 5-volt reference circuits.

1. The ignition is ON.
2. The diagnostics run continuously.

DTC P0652

1. The ECM detects the 5-volt reference 2 circuit voltage is less than 4.7 volts.
2. The above condition is present for 2 seconds.

DTC P0653

1. The ECM detects the 5-volt reference 2 circuit voltage is more than 5.2 volts.
2. The above condition is present for 2 seconds.

DTC P0652 and P0653 are Type A DTCs.

DTC P0652 and P0653 are Type A DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Output Controls»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-output-controls)
3. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)

1. The engine starts and runs.
2. Observe the 5-Volt Reference 2 Circuit Status parameter with a scan tool. The parameter should display OK.
3. Engine running, observe the DTC information with a scan tool. DTCs P0652 or P0653 should not set.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

1. Turn OFF the ignition for 30 seconds or until the ECM powers down.
2. Disconnect the accelerator pedal position (APP) sensor.
3. Turn ON the ignition, with engine OFF and measure the voltage from the 5-volt reference circuit of the APP sensor 2 to a good ground with a DMM. If the voltage measures 4.7-5.2 volts, replace the APP sensor.
4. With the DMM still connected to the 5-volt reference circuit, disconnect all other components connected to the 5-volt reference 2, one at a time. Refer to Diagnostic Fault Information above. If voltage changes when one of the above components are disconnected, replace the component. Refer to the appropriate replacement procedure.
5. Test the 5-volt reference 2 circuits for a short to ground or a short to voltage. If no problem was found in the 5-volt reference 2 circuit, replace the ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming.
2. «Accelerator Pedal Position Sensor Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
3. «Engine Oil Level Sensor and/or Switch Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-3-of-5)
4. «Fuel Sender Assembly Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0671-P0678

The glow plug controller has the ability to perform internal checks, an open or a short to ground on each of the glow plug circuits. If the glow plug controller senses a problem in a glow plug circuit, the glow plug on the affected cylinder will be disabled and the glow plug controller will send an error message to the engine control module (ECM). If this condition exists, the DTC will set.

1. The ignition is ON.
2. DTCs P0671-P0678 run continuously.

The glow plug controller detects that the glow plug control circuit is open, shorted to ground, or has more than 1 ohm of resistance.

DTCs P0671-P0678 are Type B DTCs.

DTCs P0671-P0678 are Type B DTCs.

If the battery is connected with the ignition ON, the glow plugs could be damaged without finding any circuit fault.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Engine Controls Connector End Views

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)

1. Verify that DTC P064C is not set. If DTC P064C is also set, refer to «DTC P064C»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-dtc-p029d-to-dtc-p1448) first.
2. Refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor) if you cannot duplicate the conditions.
3. Engine running, observe the DTC information with a scan tool. DTCs P0671-P0678 should not set.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

1. With the ignition ON and the glow plugs not commanded ON, probe the affected glow plug with a test lamp connected to a ground. Observe that the test lamp does not illuminate. If the test lamp does illuminate, test the glow plug control circuit for a short to voltage or for a faulty glow plug control module (GPCM). Replace the affected glow plug after repair.
2. With the ignition ON, probe the affected glow plug with an unpowered test lamp connected to ground. Command the glow plugs ON with a scan tool and observe the test lamp. If the test lamp does not illuminate, test the affected glow plug harness between the glow plug control module and the glow plug for an open, short to ground or high resistance.
3. With the ignition OFF and the affected glow plug disconnected, measure the resistance between the affected glow plug terminal and ground with a DMM for less than 1 ohm. If the resistance is more than 1 ohm, replace ALL of the glow plugs.
4. With the ignition OFF and the glow plug control module harness disconnected, measure the resistance between the affected glow plug harness connector and the glow plug control module harness connector for less than 1 ohm resistance. If the resistance is more than 1 ohm, repair the harness. If the resistance is less than 1 ohm, replace the glow plug control module.

With the igniting OFF and the affected glow plug disconnected, measure the resistance between the affected glow plug terminal of the glow plug and ground with a DMM for less than 1 ohm.

1. If the resistance is more than 1 ohm, replace the affected glow plug.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM or GPCM replacement, setup, and programming
2. «Glow Plug Replacement - Bank 1»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
3. «Glow Plug Replacement - Bank 2»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0698 or P0699

These 5-volt reference circuits are independent of each other outside the engine control module (ECM), but are bussed together inside the ECM. Therefore, a circuit condition on one sensor 5-volt reference circuit may affect the other sensor 5-volt reference circuits. The ECM monitors the voltage on the 5-volt reference circuit.

1. The ignition is ON.
2. Diagnostics run continuously.

P0698

1. The ECM detects the 5-volt reference 3 circuit voltage is less than 4.7 volts.
2. The above condition is present for 2 seconds.

P0699

1. The ECM detects the 5-volt reference 3 circuit voltage is more than 5.2 volts.
2. The above condition is present for 2 seconds.

DTCs P0698 and P0699 are Type A DTCs.

DTCs P0698 and P0699 are Type A DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Output Controls»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-output-controls)
3. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)

Engine Starts and runs.

1. Turn OFF the ignition for 60 seconds or until the ECM powers down.
2. Disconnect the accelerator pedal position (APP) sensor.
3. Turn ON the ignition, with engine OFF and measure the voltage from the 5-volt reference circuit of the APP sensor 1 to a good ground with a DMM. If the voltage measures 4.7-5.2 volts, replace the APP sensor.
4. With the DMM still connected to the 5-volt reference circuit, disconnect all other components connected to the 5-volt reference 3, one at a time. Refer to Diagnostic Fault Information above. If voltage changes when one of the above components are disconnected, replace the component. Refer to the appropriate replacement procedure.
5. Test the 5-volt reference 3 circuits for a short to ground or a short to voltage. If no problem was found in the 5-volt reference 3 circuit, replace the ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Accelerator Pedal Position Sensor Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Manifold Absolute Pressure Sensor Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
3. «Turbocharger Vane Position Sensor Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
4. «Exhaust Gas Recirculation Valve Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
5. «Control Module References»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic trouble code (DTC) indicates that an emission related transmission DTC has set in the transmission control module (TCM). The engine control module (ECM) turns ON the malfunction indicator lamp (MIL) when the TCM sends a message over the serial data circuit requesting MIL illumination.

1. The ignition is ON.
2. DTC P0700 runs continuously.

Serial Data communication from the TCM indicates a fault exists with the transmission.

DTC P0700 is a Type A DTC.

DTC P0700 is a Type A DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. DTC P0700 is an informational DTC. If there are engine controls DTCs, diagnose those first. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) for any other DTCs.
2. Engine running, observe the DTC information with a scan tool. DTC P0700 should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.
4. Engine running, observe the DTC information with a scan tool. DTC P0700 should not set.
5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P1224, P1227, P122A, P1233, P1236, P1239, P1242, or P1247

The engine control module (ECM) supplies voltage to each fuel injector on the injector positive voltage control circuits. The ECM energizes each fuel injector by grounding the control circuit of that fuel injector. The ECM monitors the status of the injector positive voltage control circuits and the fuel injector control circuits. The injectors are separated into the following four groups

1. Group 1-DTC P2146 with injectors 1 and 4
2. Group 2-DTC P2149 with injectors 6 and 7
3. Group 3-DTC P2152 with injectors 2 and 5
4. Group 4-DTC P2155 with injectors 3 and 8

When a fuel injector circuit condition is detected by the ECM, the affected fuel injectors will be disabled and may disable the affected group of fuel injectors.

1. The engine is running.
2. The charging system voltage is between 10-18 volts.

1. The ECM injector output driver detects an incorrect current on a fuel injector circuit.
2. The condition exists for 1 second.

DTCs P1224, P1227, P122A, P1233, P1236, P1239, P1242 and P1247 are Type A DTCs.

DTCs P1224, P1227, P122A, P1233, P1236, P1239, P1242 and P1247 are Type A DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Output Controls»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-output-controls)
3. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)

Observe the DTC information with a scan tool. If DTC P2146, P2149, P2152 or P2155 are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

One Fuel Injector DTC Sets

1. Disconnect the affected fuel injector connector.
2. Turn ON the ignition with the engine OFF.
3. Connect a test lamp between the affected fuel injector control circuit and a ground. The test lamp should not illuminate. If the test lamp illuminates, test the fuel injector control circuit for a short to voltage.
4. Connect a test lamp between the affected fuel injector control circuit and battery voltage. The test lamp should not illuminate. If the test lamp illuminated, test the fuel injector control circuit for a short to ground.
5. Test the affected fuel injector for high resistance. Refer to Component Testing in this diagnostic.
6. If the circuits tested normal, replace the ECM.

Two or More Fuel Injector DTCs Set

1. Test the affected group injector positive voltage control circuit for a short to ground or a short to voltage.
2. Test the affected fuel injector for high resistance. Refer to Component Testing in this diagnostic.
3. If the circuits tested normal, replace the ECM.

1. Disconnect the connector of the fuel injector to be tested.
2. Connect a DMM between the terminals of the fuel injector and measure the resistance. The resistance should be 0.2-0.3 ohms. If the resistance is more than 0.2-0.3 ohms resistance, replace the fuel injector.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Fuel Injector Replacement (Right)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2__fuel-injector-replacement-right) or «Fuel Injector Replacement (Left)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2__fuel-injector-replacement-left)
2. «Control Module References»(/chevrolet/chevy-express-h1500/2003-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, programing and setup

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

The particulates in the exhaust gases (solid particles in the exhaust exhibited as black smoke) are collected by the diesel particulate filter (DPF). When the filter becomes saturated with particulates, they are oxidized by incineration. We will refer to this incineration process as regeneration. When an active regeneration is commanded with the engine control module (ECM) a different engine calibration strategy is used to elevate the exhaust gas temperatures. The first event is to heat up the oxidation catalyst (DOC). Secondly the particulate filer temperature is elevated. These elevated exhaust gas temperatures incinerate the soot accumulated in the particulate filer.

The ECM will command a regeneration based on a calculated soot model. The soot model calculations are based on a number of different factors including

1. Distance Since Last DPF Regeneration
2. Fuel Used Since Last DPF Regeneration
3. Engine Run Time Since Last DPF Regeneration
4. Differential Pressure Sensor values

The ECM monitors the DOC and DPF temperatures with inputs from two exhaust gas temperature (EGT) sensors 1 and 2, located before and after the exhaust particulate filter. The ECM also monitors the differential backpressure in the filter by a differential pressure sensor.

If the DPF regenerations become too infrequent, this diagnostic runs and fails.

1. The engine is running.
2. DTC P1448 runs continuously once the above conditions are met.

1. The engine control module (ECM) detects that the average running of time between the last two completed DPF regenerations is greater than 20 hours, not including idle time.
2. The regeneration engine run time trigger is based on a 14 hour threshold. Therefore, the regeneration event was commanded but never completed, causing P1448 to set.

1. DTC P1448 is a type A DTC.
2. A message center or an indicator may display Clean Exhaust Filter.

DTC P1448 is a type A DTC.

1. This DTC may set if the customer ignores the Clean Exhaust Filter message or indicator and continues to drive the vehicle under conditions that do not effectively clean and/or successfully complete two regeneration events.
2. Cold ambient temperatures and short trip driving conditions may cause this DTC.
3. Several incompleted regeneration attempts may cause this DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Controls Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
2. «Engine Controls Component Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
3. «Engine Control Module Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)

Description and Operation

Diesel Particulate Filter (DPF) System Description

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List (Engine Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-list-engine-control) «Scan Tool Data List (Glow Plug Control Module)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-1-of-2__scan-tool-data-list-glow-plug)
2. «Scan Tool Data Definitions»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-1-of-2__scan-tool-output-controls)

Verify that DTCs P003A, P0047, P0048, P0101, P0201-P0208, P02A1, P02A5, P02A9, P02AD, P02B1, P02B5, P02B9, P02E0, P02E7-P02E9, P029D, P0300-P0308, P0402, P046C, P0420, P0545, P0546, P2032, P2033, P244B, P244C, P2463, or P2563 or not set.

1. If any other DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) .

Verify the integrity of the entire exhaust system by visually inspecting for the following conditions

1. Damaged exhaust system components
2. Loose or improperly installed exhaust system components
3. Leaks, or improperly routed pressure lines-The smaller tube connects to the front of the DPF. The lines should have a continuous downward gradient, without sharp bends, or kinks from the differential pressure sensor to the exhaust particulate filter assembly.

Note. After performing the system repair, perform the following: A code clear with a scan tool, regardless of whether or not a DTC is set A Diesel Particulate Filter (DPF) Service Regeneration with a scan tool Perform the above in order to remove soot from the DPF and avoid possible DPF failure.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Exhaust Particulate Filter Cleaning (DPF Service Regeneration) or Exhaust Particulate Filter Cleaning (DPF Regeneration Enable) for Service Regeneration.

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach
3. «Diagnostic Procedure Instructions»(/chevrolet/chevy-express-h1500/2003-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category

DTC P150C

Modules connected to the high and low speed GMLAN serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits for each virtual network. The messages are supervised and periodic messages are used by the receiver module as an availability indication of the transmitter module. Each message contains the identification number of the transmitter module.

1. The system voltage is between 9-16 volts.
2. The vehicle power mode requires serial data communications.

A supervised periodic message that includes the transmitter module availability has not been received, or is intermittently missing.

DTC P150C is a Type C DTC.

DTC P150C is a Type C DTC.

Use the DTC Descriptor list to determine the module which is not communicating. If there are multiple non-communicating modules in series on high speed GMLAN, choose the one closest to the data link connector (DLC) for this diagnostic.

Schematic Reference

Data Communication Schematics

Connector End View Reference

Master Electrical Component List

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__wiring-repairs)
5. «GMLAN Wiring Repairs»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Using the DTC Descriptor and Diagnostic Aids, determine which module is not communicating.
2. Ignition OFF, disconnect the harness connector at the module that is not communicating.
3. Test for less than 0.5 ohm of resistance between each ground circuit of the module that is not communicating and ground. If greater than 0.5 ohm, repair the open/high resistance in the ground circuit.
4. Test for battery voltage between each battery positive voltage circuit of the module that is not communicating and ground. If less than battery voltage, repair the short to ground or open/high resistance in the battery positive voltage circuit.
5. Ignition ON, test for battery voltage between each ignition circuit of the module that is not communicating and ground. If less than battery voltage, repair the short to ground or open/high resistance in the ignition circuit.
6. Ignition OFF, disconnect the harness connector at the module that reported the no communication DTC.
7. Ignition OFF, test for less than 0.5 ohm of resistance in each serial data circuit between the module that is not communicating and the module that reported the DTC. If greater than 0.5 ohm, repair the open/high resistance in the serial data circuit.
8. If all tests normal, replace the module that is not communicating.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for non-communicating module replacement, setup, and programming

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Engine Controls Schematics
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Powertrain Diagnostic Trouble Code (DTC) Type Definitions
• Scan Tool Data List (Engine Control Module)
• Scan Tool Data List (Glow Plug Control Module)
• Scan Tool Output Controls
• Scan Tool Data Definitions
• Contaminants-in-Fuel Diagnosis
• Diagnostic Repair Verification
• Fuel Injector Replacement (Right)
• Fuel Injector Replacement (Left)
• Control Module References
• Fuel Injector Balance Test with Tech 2
• Crankshaft Reluctor and Oil Pump Drive Gear Replacement
• Charge Air Cooler Diagnosis (Full System Air Leak Test)
• Diagnostic Trouble Code (DTC) List - Vehicle
• Exhaust Leakage
• Exhaust Particulate Filter Cleaning (DPF Service Regeneration)
• Symptoms - Engine Mechanical
• Temperature Versus Resistance (Exhaust Gas Temperature Sensor)
• Temperature Versus Resistance (Fuel Temperature Sensor)
• Temperature Versus Resistance (IAT Sensor 1)
• Temperature Versus Resistance (ECT Sensors)
• Temperature Versus Resistance (IAT Sensor 2)
• Engine Control Module Replacement
• Service Programming System (SPS)
• Instrument Cluster Schematics
• Engine Oil Level Sensor and/or Switch Replacement
• Data Communication Schematics
• Master Electrical Component List
• GMLAN Wiring Repairs
• DTC P064C