Home ReviewsRefund
Home/Chevrolet/Chevy Express H1500/Chevrolet Chevy Express H1500 (2003-2012)/Repair manual/Testing & Diagnostics/Engine Control System & Fuel System - 6.6l (Lmm) - DTC p001…
Contents Wiring diagrams Section: Testing & Diagnostics All sections

Engine Control System & Fuel System - 6.6l (Lmm) - DTC p0016 to DTC p0299 Chevrolet Chevy Express H1500

Testing & Diagnostics ~20559 words

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) provides an overview of each diagnostic category.

Circuit/System Description

The engine control module (ECM) monitors the crankshaft position (CKP) and the camshaft position (CMP) signals to determine if they are synchronized. If both signals are not observed by the ECM within a narrow time window, the ECM will determine that an error has occurred.

Conditions for Running the DTC

  1. DTCs P0335 and P0336 are not set.
  2. The engine speed is more then 50 RPM.
  3. DTC P0016 runs continuously when the above conditions are met.

Conditions for Setting the DTC

The difference between the actual and expected CKP position as calculated by the CKP sensor and CMP sensor is more than 6 degrees of crank angle or more than 12 degrees of cam angle.

Action Taken When the DTC Sets

DTC P0016 is a Type B DTC.

Conditions for Clearing the DTC

DTC P0016 is a Type B DTC.

Diagnostic Aids

  1. Inspect for any recent engine mechanical repairs. An incorrectly installed camshaft or crankshaft will cause this DTC to set.
  2. If P0016 sets the fuel injectors will be commanded OFF and the engine will not start.

Reference Information

Schematic Reference

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

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)

Circuit/System Verification

  1. If DTCs P0335, P0336, P0340, P0341, P0699 are set, test and repair those DTCs first.
  2. The engine starts and runs.
  3. Engine running, observe the DTC information with a scan tool. DTC P0016 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.

Circuit/System Testing

Inspect for the following conditions

  1. If the CKP or CMP sensor is loose and cannot be tightened replace the sensor.
  2. Remove the CKP or CMP sensor and replace if the sensor casing is broken, or rattles when shaken.
  3. Remove the front engine cover and inspect for, excessive camshaft endplay, timing gear misalignment or damage, camshaft reluctor or crankshaft reluctor damage, or for front engine cover damage.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Engine Front Cover Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-2-of-5)
  2. «Camshaft Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-2-of-5__camshaft-replacement)
  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) provide an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Turbocharger Vane Position Solenoid High ControlP003A, P0047P003A, P0047P003A
Turbocharger Vane Position Solenoid Low ControlP003A, P0047P003A, P0047P003A, P0048P003A

DTC P003A

The engine control module (ECM) performs the turbocharger (TC) learn procedure automatically when the enabling criteria's have been met. After each ignition cycle, and before the enable criteria have been met, the ECM will use the previously learned value. If the ECM does not have a previously learn value, it will default to a stored calibrated value.

The ECM performs the self learn by commanding the TC vanes to 0 percent, then to 100 percent, while monitoring the TC vane position sensor.

The positions of the TC vanes are controlled by the ECM. The ECM utilizes a TC vane control solenoid and a TC vane position sensor to control the TC vanes. The ECM will vary the boost dependant upon the load requirements of the engine. The vane control solenoid has 2 circuits, a high voltage control circuit and a low voltage control circuit. The ECM uses a pulse width modulation (PWM) on the high control and low control circuits to control the solenoid. The ECM will detect if the automatic TC learn has failed if the commanded vane position did not match the actual vane position by a calibrated threshold.

  1. DTCs P0107, P0108, P0117, P0118, P2563, P2564, P2565, P2228, P2229 are not set.
  2. The battery voltage is equal to or greater than 11 volts.
  3. The ECM is commanding the turbocharger vanes open or closed during a position learn process.
  4. The engine speed is between 600-750 RPM.
  5. The engine coolant temp (ECT) is between 73-96°C (163-205°F).
  6. The calculated fuel rate is less than 30 mm 3 .
  7. DTC P003A runs once per key cycle when the above conditions are met.

The ECM did not detect a valid learn within 30 seconds.

DTC P003A is a Type B DTC.

DTC P003A is a Type B DTC.

  1. If there is a loss of ignition voltage to the ECM terminal C1-76 this DTC may set. Verify this circuit is not shorted to ground/open, or the supply fuse for this circuit is not open.
  2. If any service has been performed on the turbocharger or on the turbocharger components, a turbocharger relearn must be performed. Failure to perform the turbocharger learn procedure may cause other DTCs to set. Refer to «Turbocharger Learn»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-2-of-2__turbocharger-learn) .

Schematic Reference

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

  1. «Turbocharger System Description»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
  2. «Turbocharger Learn»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-2-of-2__turbocharger-learn)

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

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 Required

J 34730-405 Injector Test Lamp

  1. Verify that DTCs P0047, P0048, P0652, P0653, P0698, P0699, P2564, or P2565 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. Engine running, increase the engine speed to 1,500 RPM and maintain. Command the TC Vane Pos. Ctrl. Solenoid ON and OFF with a scan tool. Observe the Vane Position Sensor parameter. The TC Vane Position Sensor parameter should increase to 95-97 percent and decrease to near 0 percent when commanded ON and OFF.
  3. Engine running, observe the TC Vane position Sensor and the Desired TC Vane Position parameters with a scan tool. Slowly increase the engine speed from idle to 2,500 RPM, and slowly return the engine to idle speed. The TC Vane Position Sensor parameter should remain near or equal to the Desired TC Vane Position parameter throughout the engine speed range.
  4. Engine running, observe the TC Vane Position Sensor and the Desired TC Vane Position parameters while increasing the TC vane position in 5 percent increments from 0-100 percent with a scan tool. The parameters should remain within 2 percent of each other during the entire range.
  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.
IMPORTANTYou must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
  1. Ignition OFF, for 90 seconds, disconnect the harness connector at the TC control solenoid.
  2. Connect the J 34730-405 between the high control Terminal A and the low control circuits Terminal B.
  3. Engine running, engine coolant temperature (ECT) sensor 1 must be less than 70°C (158°F). Command the TC Vane Pos. Ctrl. solenoid ON and OFF with a scan tool. The test lamp should change from bright to dim when changing between the commanded states. If the test lamp does not change brightness, test the low control circuit Terminal A for a short to voltage. If the circuit tests normal, test the low control Terminal A and high control circuits Terminal B for a short to ground or an open/high resistance. If the circuits test normal, replace the ECM.
  4. Ignition OFF, measure the resistance of the TC control solenoid. The reading should be between 3-7 ohms. If the resistance is not within the specified range, replace the TC control solenoid.
  5. Test for infinite resistance between each TC control solenoid terminal and the TC control solenoid housing. If less than infinite resistance, replace the TC control solenoid.
  6. Disconnect the harness connectors at the ECM, and TC vane position sensor.
  7. Test for less than 5 ohms of resistance on all circuits between the following terminals: The ECM C1 TC solenoid high control circuit terminal 48 to TC control solenoid terminal A. The ECM C1 TC solenoid low control circuit terminal 96 to TC control solenoid terminal B. The ECM C1 TC sensor signal circuit terminal 20 to TC position sensor terminal B. The ECM C1 TC sensor low reference terminal 63 to TC position sensor terminal C. The ECM C1 TC sensor 5-volt reference terminal 13 to TC position sensor terminal D. If greater than the specified range, repair the high resistance in the affected circuit.
  8. Connect the ECM connectors. Test the TC vane position sensor. Refer to Component Testing in this document for instructions.
  9. Install and connect the TC vane position sensor.
  10. Inspect the turbocharger for debris, damage, or sticking vanes. Refer to «Turbocharger Cleaning and Inspection»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-4-of-5__turbocharger-cleaning-and-inspection) .
  11. If all circuits, the TC control solenoid, and the TC vane position sensor tests are normal, replace the turbocharger assembly.

Component Testing

IMPORTANTYou must perform the Circuit/System Testing in order to verify the integrity of the TC vane position sensor circuits before proceeding with the Component Testing.

TC Vane Position Sensor

  1. Ignition OFF, remove the TC vane position sensor.
  2. Connect the harness connector to the TC vane position sensor.
  3. Ignition ON, slowly depress the button on the end of the TC position sensor while observing the TC Vane Position Sensor parameter on the scan tool for a smooth decreasing percentage from 100-0 percent without any spikes or dropouts. If the TC Vane Position Sensor parameter is erratic, replace the TC vane position sensor.
  1. «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)
  2. «Turbocharger Control Solenoid Valve Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
  3. «Turbocharger Replacement (LLY, LBZ)»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-2-of-5__turbocharger-replacement-lly-lbz) or «Turbocharger Replacement (LMM)»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-2-of-5__turbocharger-replacement-lmm)
  4. «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

Repair Verification

  1. Engine running, observe the scan tool TC Vane Position Sensor and the Desired TC Vane Position parameters. Slowly increase the engine speed to 2,500 RPM, and slowly return the engine speed to an idle. The TC Vane Position parameter should remain near or equal to the Desired TC Vane Position parameter.
  2. Engine running, observe the scan tool TC Vane Position Sensor parameter while increasing the engine speed to 1,500 RPM and maintaining. Command the TC Vane Pos. Ctrl. Solenoid ON and OFF. The TC Vane Position Sensor parameter should increase to 95-97 percent when the TC solenoid is commanded ON, and decrease to near 0 percent when commanded OFF.
  3. Engine running, observe the scan tool TC Vane Position Sensor and the Desired TC Vane Position parameters while increasing the TC vane position sensor in 5 percent increments from 0-100 percent. The TC Vane Position Sensor and the Desired TC Vane Position parameters should remain within 2 percent of each other during the entire range.
  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.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Turbocharger Vane Position Solenoid High ControlP003A, P0047P003A, P0047P003A
Turbocharger Vane Position Solenoid Low ControlP003A, P0047P003A, P0047P003A, P0048P003A

DTC P0047 or P0048

The positions of the turbocharger vanes are controlled by the engine control module (ECM). The ECM utilizes a turbocharger vane control solenoid to control the turbocharger vanes and a turbocharger vane position sensor to verify the vanes position. The ECM will vary the boost dependant upon the load requirements of the engine. The vane control solenoid has 2 circuits, a high control circuit and a low control circuit. The ECM uses a pulse width modulation on both circuits to control the solenoid.

  1. The engine run time is greater than 60 seconds.
  2. DTCs P0047 and P0048 run continuously when the above condition is met.
  1. The control module detects that the commanded state of the driver and the actual state of the control circuits do NOT match.
  2. The above condition exists for equal to or greater than 4 seconds.

DTCs P0047 and P0048 are Type B DTCs.

DTCs P0047 and P0048 are Type B DTCs.

If there is a loss of ignition voltage to the ECM terminal C1-76 this DTC may set. Verify this circuit is not shorted to ground or open. Verify the supply fuse for this circuit is not open.

Schematic Reference

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)
  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

  1. «Turbocharger System Description»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
  2. «Turbocharger Learn»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-introduction-2-of-2__turbocharger-learn)

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

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 Required

J 34730-405 Injector Test Lamp

  1. Verify that DTCs P0652, P0653, P0698, P0699, P2564, or P2565 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. Engine running, increase the engine speed to 1,500 RPM and maintain. Command the TC Vane Pos. Ctrl. Solenoid ON and OFF with a scan tool while observing the Vane Position Sensor parameter. The TC Vane Position Sensor parameter should increase to 95-97 percent and decrease to near 0 percent when changing between the commanded states.
  3. Engine running, observe the TC Vane Position Sensor and the Desired TC Vane Position parameters with a scan tool. Slowly increase the engine speed from idle to 2,500 RPM, and slowly return the engine to idle speed. The TC Vane Position Sensor parameter should remain near or equal to the Desired TC Vane Position parameter throughout the engine speed range.
  4. Engine running, observe the TC Vane Position Sensor and the Desired TC Vane Position parameters while increasing the TC vane position in 5 percent increments from 0-100 percent with a scan tool. The parameters should remain within 2 percent of each other during the entire range.
  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.
  1. Ignition OFF, disconnect the harness connector at the TC vane control solenoid.
  2. Connect the J 34730-405 between the high control circuit Terminal A and the low control circuit Terminal B.
  3. Engine running, engine coolant temperature (ECT) sensor 1 is less than 70°C (158°F). Command the TC Van Pos. Ctrl. solenoid ON and OFF with a scan tool. The test lamp should change from bright to dim when changing between the commanded states. If the test lamp does notchange brightness, test the low control circuit Terminal A for a short to voltage. If the circuit tests normal, test the low control circuit Terminal A and high control circuit Terminal B for a short to ground or an open/high resistance. If the circuits test normal, replace the ECM.
  4. Ignition OFF, test for a resistance between 2-7 ohms across the terminals of the TC vane control solenoid. If the resistance is not within the specified range, replace the TC vane position solenoid.
  5. Test for infinite resistance between each terminal and the TC vane control solenoid housing. If less than infinite resistance, replace the TC vane control solenoid.
  6. If all circuits test normal, replace the TC control vane control solenoid.

Perform the Turbocharger Learn , then review the DTC information with a scan tool.

  1. «Turbocharger Control Solenoid 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. Engine running, observe the scan tool TC Vane Position Sensor and the Desired TC Vane Position parameters. Slowly increase the engine speed to 2,500 RPM, and slowly return the engine speed to idle. The TC Vane Position parameter should remain near or equal to the Desired TC Vane Position parameter.
  2. Engine running, observe the scan tool TC Vane Position Sensor parameter while increasing the engine speed to 1,500 RPM and maintaining. Command the TC Vane Pos. Ctrl. Solenoid ON and OFF. The TC Vane Position Sensor parameter should increase to 95-97 percent when the TC solenoid is commanded ON, and decrease to near 0 percent when commanded OFF.
  3. Engine running, observe the scan tool TC Vane Position Sensor and the Desired TC Vane Position parameters while increasing the TC vane position sensor in 5 percent increments from 0-100 percent. The TC Vane Position Sensor and the desired TC Vane Position parameters should remain within 2 percent of each other during the entire range.
  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.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
FRP Sensor 5-Volt ReferenceP0117, P0522, P0652, P0700P0087, P0191, P0192, P0700P0193P0533, P0653
FRP Sensor SignalP0192P0191P0193P0193
Fuel Pressure Regulator Solenoid Supply VoltageP0088, P0090P0088P0090P0087, P0191, P2510
Fuel Pressure Regulator Solenoid ControlP0088, P0090P0088P0090P0090

DTC P0087 or P0088

The fuel injection pump supplies high pressure fuel to the fuel injection rails, and then to the fuel injectors through high pressure pipes. The fuel rail pressure (FRP) sensor is a three wire sensor mounted in the right fuel injection rail. The FRP sensor uses a 5-volt reference circuit, a signal circuit, and a low reference circuit to monitor fuel rail pressure. This information is sent to the engine control module (ECM) to assist in the fueling of the engine.

P0087

  1. DTCs P0090, P0192, P0193 are not set.
  2. The engine is running.

P0088

  1. DTCs P0087, P0192, P0193 are not set.
  2. The engine is running.

P0087

  1. The actual FRP is more than 15 MPa (2,176 psi) below the desired FRP. OR
  2. The actual FRP is less than 22.5 MPa (3,263 psi).

P0088

  1. The actual FRP is more than 20 MPa (2,900 psi) above the desired FRP. OR
  2. The actual FRP is more than 189 MPa (27,412 psi)
  1. DTCs P0087 and P0088 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 MIL/DTC

DTCs P0087 and P0088 are Type A DTCs.

P0087

  1. Gasoline contamination of the fuel may cause this DTC to set. Refer to «Contaminants-in-Fuel Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-troubleshooting-diagnosis__contaminants-in-fuel-diagnosis) .
  2. When ambient temperatures are below 0°C (32°F), the fuel tank pickup screen may be iced over from water in the fuel tank.
  3. When power enhancing devices have been attached to the fuel rail pressure sensor circuits, this DTC may set and adversely effect the fuel system components.
  4. If the fuel pressure valve is not torqued correctly, the valve will leak fuel into the fuel return system causing this DTC to set. The fuel pressure relief valve uses a bite type seal, and proper torque is essential for valve to rail sealing. Refer to «Fastener Tightening Specifications»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2__fastener-tightening-specifications) .
  5. High fuel injector return flow may cause this DTC to set.
  6. The addition of fuel system enhancements, such as auxiliary fuel tanks or add on fuel filters may relate to driveability complaints.

P0088

  1. Driveability concerns may not occur with this DTC present.
  2. If the fuel system pressure is actually too high, a fuel knock will exist.
  3. A sticking FRP regulator may cause this DTC to set.

Schematic Reference

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

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)

Special Tools Required

CH-48027 Digital Pressure Gage

  1. With engine running, observe the Actual Fuel Rail Pressure parameter with a scan tool. A normal reading would be approximately 40 MPa (5,802 psi) with the engine cold, and 30 MPa (4,351 psi) at operating temperature.
  2. Engine running, observe the DTC information with a scan tool. DTCs P0087 or P0088 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.

P0087

  1. If DTC P0090, P0168 or P0191 is also 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. Install the CH-48027 to the fuel rail service port and slowly increase the engine speed until reaching wide open throttle (WOT). If more than 5 inches Hg of vacuum was present during engine speed increase, replace the fuel filter and inspect the fuel supply lines for damage between the fuel tank and the fuel injection pump. If no restriction were found, test for high fuel return flow. Refer to «Fuel System Diagnosis - High Pressure Side»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-troubleshooting-diagnosis)
  4. With the engine idling or at an idle, command the fuel pressure control to 180 MPa (23,206 psi) with a scan tool. Observe the Actual Fuel Rail Pressure parameter. The actual fuel pressure should be the same as the commanded pressure. If the Actual Fuel Rail Pressure is less than 165 MPa (23,931 psi), refer to «Fuel System Diagnosis - High Pressure Side»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-troubleshooting-diagnosis) .
  5. Operate the vehicle within the conditions for which the customer complaint occurs while observing the CH-48027 . You may also operate the vehicle within the conditions that you observed in the Freeze Frame/Failure Records. If the vacuum was more than 12 inches Hg of vacuum at any time in the operating range, inspect for kinked or restricted fuel supply lines.
  6. Operate the vehicle within the conditions for which the customer complaint occurred. Observe the Actual fuel Rail Pressure and Desired Fuel rail Pressure parameters with a scan tool. Fuel pressures should be the same for both parameters. If the Actual Fuel Rail Pressure is less than the Desired Fuel Rail Pressure, refer to «Fuel System Diagnosis - High Pressure Side»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-troubleshooting-diagnosis) . If fuel system tests normal, refer to Diagnostic Aids.

P0088

  1. Start the engine and 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/Failure Records.
  2. Observe the Actual Fuel Pressure parameter with a scan tool. The actual pressure should be 30 MPa (4,352 psi) with the engine idling at operating temperature.
  3. Command the fuel pressure with a scan tool, incrementing through the entire fuel pressure range. The fuel pressure should increment and stabilize through the entire fuel pressure range with actual and desired fuel pressure within 5 MPa (725 psi) of each other. If the pressure difference between the actual and desired pressure are more than 5 MPa (725 psi), test the solenoid supply voltage circuit and the solenoid control circuit for high resistance or a short to ground. If the circuits test normal, replace the FRP regulator. If the pressure difference between the actual and desired pressure is less than 5 MPa (725 psi), refer to Diagnostic Aids.

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.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
Solenoid Supply VoltageP0088, P0090P0088P0090P0087, P0191
Solenoid ControlP0088, P0090P0088P0090P0090

DTC P0090

High pressure fuel is regulated by the fuel rail pressure (FRP) regulator mounted on the fuel injection pump. The FRP regulator is controlled by the engine control module (ECM). The FRP regulator has a solenoid supply voltage circuit and solenoid control circuit. The ECM monitors the current on the circuits to detect a failure.

  1. The ignition is ON.
  2. The commanded FRP regulator current is between 40-1,500 mA.

The FRP regulator circuit current is not between 40-1,600 mA.

  1. DTC P0090 is a Type A DTC.
  2. The control module commands the engine to operate in the Reduced Engine Power mode.
  3. The message center displays Reduced Engine Power.

DTC P0090 is a Type A DTC.

  1. There are no driveability concerns associated with the FRP regulator unless a DTC is present. The most likely cause of this DTC is a sticking FRP regulator.
  2. If the fuel system pressure is actually too high, a fuel knock condition will exist.
  3. If the fuse that supplies voltage to terminal C1-76 of the ECM is open, this DTC will set.

Schematic Reference

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

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 Required

  1. CH-48027 Digital Pressure Gage
  2. J 35616-200 Test Light Probe Kit
IMPORTANTIf you cannot duplicate the condition, 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/Failure Records.
  1. Turn ON the ignition and observe that the Desired FRP Regulator parameter and the FRP Regulator Command are at the same mA values. The FRP Regulator Command should be at 16 percent.
  2. The fuel pressure difference between the Actual Fuel Rail Pressure and the Desired Fuel Rail Pressure should be less than 5 MPa.
  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. DTC P0090 should not set.
IMPORTANTFailure to allow the ECM communications to completely terminate with the scan tool may result in misdiagnosis.

If DTC U0105, is also set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

  1. Turn OFF the ignition for 30 seconds or until the ECM is powered down.
  2. Disconnect the FRP regulator in-line connector.
  3. Probe the solenoid control circuit terminal 2 with a test lamp connected to ground. The test lamp should not illuminate. IMPORTANT: A solenoid control circuit that is shorted to voltage will illuminate the test lamp on both the supply voltage circuit and the solenoid control circuit. If the test lamp illuminates, test the solenoid control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Turn ON the ignition.
  5. Connect the test lamp between the solenoid supply voltage circuit, terminal 1 and a ground. The test lamp should illuminate. If the test lamp did not illuminate, test the solenoid supply voltage circuit for an open. If the circuit tests normal, replace the ECM.
  6. Connect the test lamp between the solenoid supply voltage circuit, terminal 1 and the solenoid control circuit, terminal 2. The test lamp should illuminate. If the test lamp did not illuminate, test the solenoid control circuit for an open. If the circuit tests normal, replace the ECM.
  7. Test the harness between the inline connector and the FRP regulator for an open or short to voltage. If the circuits tests normal, replace the FRP regulator.

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)
  2. «Fuel Pressure Regulator 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.
CircuitShort to GroundOpenHigh ResistanceShort to VoltageSignal Performance
IAT Sensor 2 SignalP0097P0098P0116P0098P0098' P0116
IAT Sensor 2 Low ReferenceP0098P0116P0098

DTC P0097 or P0098

Typical Scan Tool Data

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Ignition ON or Engine Running Parameter Normal Range: -39°C to +120°C (-38°F to +248°F)
IAT Sensor 2 Signal140°C (284°F)40°C (-40°F)40°C (-40°F)
IAT Sensor 2 Low Reference40°C (-40°F)40°C (-40°F)

IAT Sensor 2

The intake air temperature (IAT) sensor 2 is a variable resistor. The IAT sensor 2 has a signal circuit and a low reference circuit. The IAT sensor 2 measures the temperature of the air at the engines intake manifold. The engine control module (ECM) supplies 5 volts to the IAT sensor 2 signal circuit, and a ground for the IAT sensor 2 low reference circuit. When the IAT sensor 2 is cold, the sensor resistance is high. When the intake manifold air temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the IAT sensor 2 signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the IAT sensor 2 signal circuit. The ECM continuously monitors the IAT sensor 2 signal voltage for an excessively high or low voltage, or a voltage signal that is not in correlation with the engine coolant temperature (ECT) sensor 1.

DTC P0097 and P0098 run continuously within the enabling conditions.

P0097

The IAT sensor 2 is greater than 148°C (298°F) for greater than 1 second. This is equal to or less than 0.10 volt on the IAT sensor 2 signal circuit as measured by the ECM.

P0098

The IAT sensor 2 is less than -39°C (-38°F) for greater than 1 second. This is equal to or greater than 4.8 volts on the IAT sensor 2 signal circuit as measured by the ECM.

DTCs P0097 and P0098 are Type B DTCs.

DTCs P0097 and P0098 are Type B DTCs.

Schematic Reference

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)

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

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. Ignition ON, observe the scan tool IAT Sensor, IAT Sensor 2, and ECT Sensor parameters. The reading should be within 15°C (27°F) of each other and also the ambient temperature.
  2. Engine running, observe the DTC information with a scan tool. DTCs P0097 or P0098 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 IAT sensor 2.
  2. Ignition OFF, for 90 seconds, test for less than 5 ohms 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.
  3. Ignition ON, verify the scan tool IAT Sensor 2 parameter is less than -39°C (-38°F). If greater than the specified range, test the signal circuit terminal A 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 the low reference circuit terminal B. Verify the scan tool IAT Sensor 2 parameter is greater than 130°C (266°F). If less 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 or replace the IAT sensor 2.

Static Test

  1. Ignition OFF, disconnect the harness connector at the IAT sensor 2.
  2. Measure the resistance between the signal terminal A and the low reference circuit terminal B.
  3. Compare the value to the Temperature Vs Resistance table. Verify the resistance is within 9 percent of the specification. Refer to «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) . If not within the specified range, replace the IAT sensor 2.

Dynamic Test

  1. Test the IAT sensor 2 by varying the sensor temperature while monitoring the sensor resistance.
  2. Compare the readings with the Temperature Vs Resistance table and verify that the resistance is within 9 percent of the specification. If not within the specified range, replace the IAT sensor 2.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Intake Air Temperature (IAT) Sensor 2 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 engine control module (ECM) uses the fuel rail pressure (FRP) sensor to monitor the high side fuel pressure and the fuel rail pressure relief valve performance. The fuel rail pressure relief valve is designed to release fuel pressure in the event of an overpressure condition. This diagnostic looks for excessive fuel rail pressure decay to detect an open fuel rail pressure relief valve.

  1. Engine is running.
  2. Fuel rail pressure is more than 189 MPa.
  3. This diagnostic runs continuously.
  1. The stored fuel pressure deviation values, during three diagnostic events, are all above the calibrated limits OR
  2. The sum of the stored fuel pressure deviation values are above the calibrated limits OR
  3. One or two fuel pressure deviation values are above the calibrated limits and the fuel rail pressure valve is stuck in the open position.
  1. DTC P009E is a type A DTC.
  2. The control module commands the engine to operate in the Reduced Engine Power mode.
  3. A message center displays Reduced Engine Power

DTC P009E is a type A DTC.

  1. The most likely cause of this code setting intermittently is the fuel pressure relief valve.
  2. A restricted fuel filter may cause this DTC to set.
  3. Fuel level below 11 percent may cause this DTC to set.

Schematic Reference

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

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)

If any other DTCs are set other than DTC P009E, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

  1. Remove the fuel pressure relief valve return hose and plug the hose to prevent fuel leakage.
  2. Install a section of rubber fuel hose on the fuel pressure relief valve connection and place loose end of hose into a clean fuel container. IMPORTANT: Fuel that is contaminated with gasoline may cause permanent damage to the fuel pressure relief valve. Refer to «Contaminants-in-Fuel Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-troubleshooting-diagnosis__contaminants-in-fuel-diagnosis) . If the engine cranks but does not start, crank the engine for 15 seconds. Observe for no fuel leaking from fuel pressure relief valve. If fuel leaks from the fuel pressure relief valve, replace the pressure relief valve. Refer to «Fuel Pressure Relief Valve Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2) .
  3. If the engine starts and runs, idle the engine while commanding the fuel rail pressure to 180 MPa with a scan tool. Observe for no fuel leaking from fuel pressure relief valve.
  1. If fuel leaks from the fuel pressure relief valve, replace the pressure relief valve. Refer to «Fuel Pressure Relief Valve Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2) .
  1. If the circuits test normal, go to Diagnostic Aids.

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.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
Ignition 1 VoltageP0102P0101P0102P0102P0101
MAF Sensor SignalP0102P0102P0102P0101, P0102, P0401P0101
Low Reference

DTC P0101

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine Running at various operating conditions Parameter Normal Range: 2,300-9,000 Hz
Ignition 1 voltage65535 Hz65535 Hz
MAF Sensor Signal65535 Hz65535 Hz65535 Hz
Low Reference

MAF Sensor

The mass air flow (MAF) sensor is integrated with the intake air temperature (IAT) sensor. The MAF sensor is an air flow meter that measures the amount of air entering the engine. The engine control module (ECM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF/IAT sensor has the following circuits

  1. A MAF sensor ignition 1 voltage circuit
  2. A MAF sensor ground circuit
  3. A MAF sensor signal circuit
  4. An IAT sensor signal circuit
  5. An IAT sensor low reference circuit

The ECM applies 5 volts to the MAF sensor on the MAF sensor signal circuit. The sensor uses the voltage to produce a frequency based on the inlet airflow through the sensor bore. The frequency varies in a range depending on engine coolant temperature (ECT) of approximately 2,300 Hertz at idle to near 9,000 Hertz at maximum engine load.

  1. DTCs P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0642, P0643, P0652, P0653, P0698, P0699, P2228, P2229 are not set.
  2. The intake air temperature (IAT) is greater than -20°C (-4°F).
  3. The engine coolant temperature (ECT) is less than 99°C (210°F).
  4. The BARO is greater than 72 kPa.
  5. The engine speed is greater than 500 RPM.
  6. The exhaust gas recirculation (EGR) valve is not commanded ON.
  7. This DTC runs continuously within the enabling conditions.

The ECM detects that the MAF sensor air flow ratio is not within a predetermined range of the calculated MAF air flow ratio for greater than 16 seconds.

  1. DTC P0101 is a Type A DTC.
  2. The ECM commands reduced engine power as a remedial action.
  3. The driver information center or indicator may display reduced engine power.

DTC P0101 is a Type A DTC.

  1. A slight to moderate resistance of 10-20 ohms on the MAF sensor ignition 1 voltage circuit may cause this DTC to set.
  2. A skewed MAF sensor, an intake air flow restriction or any unmetered air that enters the engine downstream of the MAF sensor may cause this DTC to set.
  3. A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 6-38 g/s at idle to 380 g/s or more at the time of the 2-3 shift.
  4. An aftermarket exhaust system may reduce engine back-pressure excessively and cause this DTC to set.

Schematic Reference

Connector End View Reference

  1. «Engine Controls Component 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 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

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 Required

J 38522 Variable Signal Generator

  1. Verify that DTCs P0047, P0048, P0102, P0103, P0403, or P0405 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 restrictions do not exist in the exhaust system. Refer to «Restricted Exhaust»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system) .
  3. Verify that leaks do not exist in the exhaust system. Refer to «Exhaust Leakage»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system__exhaust-leakage) .
  4. Engine operating at idle; observe the scan tool MAF Sensor parameter. The reading should be between 2,300-4,400 HZ depending on the ECT temperature.
  5. A WOT acceleration from a stop should cause the MAF Sensor parameter on the scan tool to increase rapidly. This increase should be from 16-38 g/s at idle to greater than 400 g/s at the time of the 1-2 shift.
  6. 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.
IMPORTANTYou must perform the Circuit/System Verification before proceeding with the circuit/system testing.
  1. Verify the integrity of the entire air induction system by inspecting for the following conditions: A loose or disconnected charge air cooler hose or pipe A restricted or collapsed air intake duct A misaligned or damaged air intake duct A dirty or deteriorating air filter element Any objects blocking the air inlet probe of the MAF/IAT sensor Any contamination or debris on the sensing elements in the probe of the MAF/IAT sensor A cracked or damaged MAF sensor housing Any water intrusion in the induction system Any snow or ice build-up a the air cleaner, MAF or MAP sensors in cold climates An intake manifold leak A MAP sensor seal that is missing or damaged An Intake Manifold Resonator with a leaking seal, or a cracked or broken housing
  2. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
  3. Ignition OFF for 90 seconds, test for less than 5 ohms of resistance between the low reference circuit terminal 2 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.
  4. Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit terminal 3 and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  5. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal 1 and ground. If less than the specified range, test the MAF signal 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 MAF signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  6. Test the charge air cooler system for leaks. Refer to «Charge Air Cooler Diagnosis (Charge Air Cooler Air Leak Test)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-troubleshooting-diagnosis) «Charge Air Cooler Diagnosis (Full System Air Leak Test)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-troubleshooting-diagnosis) .
  7. Remove the air inlet tube to intake manifold. Refer to «Exhaust Gas Recirculation and Cooler Removal»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-3-of-5__exhaust-gas-recirculation-and-cooler-removal) . Perform steps 1-6.
  8. Visually inspect the EGR valve and verify the valve is in the closed position. If the EGR valve is not in the closed position, replace the EGR valve.
  9. If all circuits, the charge air cooler, and EGR valve test normal, test the MAF/IAT sensor.
IMPORTANTYou must perform the Circuit/System Testing in order to verify the integrity of the MAF sensor circuits before proceeding with the Component Testing.

To determine if the ECM can properly process the MAF sensor frequency signal, connect the J 38522 to the vehicle as follows

  1. Turn OFF the ignition, disconnect the connector at MAF/IAT sensor.
  2. Connect the battery voltage supply and ground the black lead.
  3. Connect the red lead to the signal circuit terminal A of the MAF sensor.
  4. Set the duty cycle switch to Normal.
  5. Set the Frequency switch to 5 K.
  6. Set the signal switch to 5 volts.
  7. Start the engine, observe the MAF Sensor parameter for the correct range of 4,950-5,025 Hz. If the MAF Sensor parameter is not within the specified range, replace the ECM. If the MAF Sensor parameter is within the specified range, replace the MAF sensor.

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)
  2. «Mass Airflow Sensor/Intake Air Temperature 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) provide an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
Ignition 1 VoltageP0102P0101P0102P0102P0101
MAF Sensor SignalP0102P0101P0102P0101, P0401P0101
Low Reference

DTC P0102 or P0103

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine Running at idle, ECT sensor 1 greater than 60°C (140°F) Parameter Normal Range: 4,000-4,400 Hz Operating Conditions: Engine Running at idle, ECT sensor 1 less than 60°C (140°F) Parameter Normal Range: 2,400-3,100 Hz
Ignition 1 Voltage65535 Hz65535 Hz
MAF Sensor Signal65535 Hz65535 Hz65535 Hz
Low Reference

MAF Sensor

The mass air flow (MAF) sensor is integrated with the intake air temperature (IAT) sensor. The MAF sensor is an air flow meter that measures the amount of air entering the engine. The engine control module (ECM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF/IAT sensor has the following circuits

  1. A MAF sensor ignition 1 voltage circuit
  2. A MAF sensor ground circuit
  3. A MAF sensor signal circuit
  4. An IAT sensor signal circuit
  5. An IAT sensor low reference circuit

The ECM applies 5 volts to the MAF sensor on the MAF sensor signal circuit. The sensor uses the voltage to produce a frequency based signal on the inlet airflow through the sensor bore. The frequency varies in a range depending on engine coolant temperature (ECT) sensor 1 of approximately 2,400 Hertz at idle to near 17,500 Hertz at maximum engine load.

P0102

  1. The engine is running for greater than 2 seconds.
  2. The engine speed is between 500-3,100 RPM.
  3. The above conditions are met for more than 3 seconds.
  4. This DTC runs continuously within the enabling conditions.

P0103

  1. The engine is running for greater than 2 seconds
  2. The above conditions are met for greater than 3 seconds.
  3. This DTC runs continuously within the enabling conditions.

P0102

The ECM detects that the MAF sensor is less than 3.6 g/s for greater than 3 seconds.

P0103

The ECM detects that the MAF sensor is greater than 527 g/s for greater than 3 seconds.

DTCs P0102 and P0103 are Type B DTCs.

DTCs P0102 and P0103 are Type B DTCs.

  1. A wide open throttle (WOT) acceleration from a stop should cause the MAF Sensor parameter on the scan tool to increase rapidly. This increase should be from 21-39 g/s at idle to greater than 380 g/s at the time of the 1-2 shift.
  2. For an intermittent problem, visually and physically inspect the exhaust gas recirculation (EGR) valve for a possible binding or sticking in the open position.
  3. Verify that any electrical aftermarket devices are properly connected and grounded. Refer to «Checking Aftermarket Accessories»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__checking-aftermarket-accessories) .

Schematic Reference

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

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)

Special Tools Required

J 38522 Variable Signal Generator

  1. Verify that the following DTCs are not set: P003A, P0047, P0048, P0106, P0403, P0405, P0406, P046C, P02E2, P02E3, P02E7, P02E8, or P02E9. 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. Engine running at idle, observe the scan tool MAF Sensor parameter. The reading should be between 2,400-4,400 Hz depending on the ECT sensor 1.
  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. Verify the integrity of the entire air induction system by inspecting for the following conditions: Damaged components Loose or improper installation Restrictions or leaks in the air induction system Water intrusion In cold climates, inspect for any snow or ice build-up.
  2. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
  3. Ignition OFF for 90 seconds, test for less than 5 ohms of resistance between the low reference circuit terminal 2 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.
  4. Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit terminal 3 and ground. If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance.
  5. Ignition ON, test for 4.8-5.2 volts between the MAF signal circuit and ground. If less than the specified range, test the MAF signal 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 MAF signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  6. Remove the air inlet tube to the intake manifold. Refer to «Exhaust Gas Recirculation Valve Cooler Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2) . Perform steps 1-6.
  7. Visually inspect the EGR valve and verify the valve is in the closed position. If the EGR valve is not in the closed position, replace the EGR valve. If the EGR valve inspection is normal, replace the MAF/IAT sensor.
  8. If all circuits and the EGR valve test normal, test or replace the MAF sensor.
IMPORTANTYou must perform the Circuit/System Testing in order to verify the integrity of the MAF sensor circuits before proceeding with the Component Testing.

To determine if the ECM can properly process the MAF sensor frequency signal, connect the J 38522 to the vehicle as follows

  1. Turn OFF the ignition.
  2. Connect the battery voltage supply and ground the black lead.
  3. Connect the red lead to the signal circuit terminal A of the MAF sensor.
  4. Set the duty cycle switch to Normal.
  5. Set the Frequency switch to 5 K.
  6. Set the signal switch to 5 volts.
  7. Start the engine, observe the MAF Sensor parameter for the correct range of 4,950-5,025 Hz. If the MAF Sensor parameter is not within the specified range, replace the ECM. If the MAF Sensor parameter is within the specified range, replace the MAF sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Mass Airflow Sensor/Intake Air Temperature Sensor Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
  2. «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)
  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.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
5-Volt ReferenceP0107, P0698, P2564P0106P0107P0106, P0401, P0699, P2565P0106
MAP Sensor SignalP0107P0106P0108P0108P0106
Low ReferenceP0106P0108P0106

DTC P0106

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine Running Parameter Normal Range: Varies, 54-253 kPa
5-Volt Reference43 kPa43 kPa200-205 kPa
MAP Sensor Signal43 kPa43 kPa255 kPa
Low Reference255 kPa

MAP Sensor

The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by turbocharger output, engine speed, accelerator pedal input, air temperature, and barometric pressure (BARO). A diaphragm within the MAP sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The engine control module (ECM) supplies a regulated 5 volts to the sensor on the 5-volt reference circuit. The ECM supplies a ground on the low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to the pressure changes, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value. Under normal operation, the lowest pressure that can exist in the intake manifold is equal to the BARO. This occurs when the vehicle is operating at idle or when the ignition is ON, while the engine is OFF. The ECM uses the MAP sensor to aid in diagnosis of the turbocharger performance. The highest manifold pressures occur when the turbocharger output is high. Manifold pressure can range from 58 kPa (8 psi) when pressure are low, to more than 240 kPa (34 psi) when pressures are high, depending on the BARO. The MAP sensor has a range of 43-255 kPa (6-36 psi).

  1. DTCs P0107, P0108, P2228, P2229 are not set.
  2. The engine speed is less than 760 RPM.
  3. The exhaust gas recirculation (EGR) valve is not commanded ON.
  4. This DTC runs continuously within the enabling conditions.

The ECM detects that the BARO and MAP sensors disagree by more than 14 kPa with the ignition ON, for more than 10 seconds.

  1. DTC P0106 is a Type A DTC.
  2. The ECM commands reduced engine power mode.
  3. A message center or an indicator may display Reduced Engine Power.

DTC P0106 is a Type A DTC.

  1. A slight resistance of 20-30 ohms on the 5-volt reference or low reference circuits may cause this DTC to set.
  2. Verify that any electrical aftermarket devices are properly connected and grounded. Refer to «Checking Aftermarket Accessories»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__checking-aftermarket-accessories) .

Schematic Reference

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)
  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)

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

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 Required

  1. J 23738-A Mityvac
  2. J 35555 Metal Mityvac
  1. Verify that DTCs P0698 or P0699 are not set. If any of the DTCs are set, refer to «DTC P0698 or P0699»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-dtc-p029d-to-dtc-p1448) .
  2. Verify that restrictions do not exist in the exhaust system. Refer to «Restricted Exhaust»(/chevrolet/chevy-express-h1500/2003-2012/remont/exhaust/#engine-exhaust-system) .
  3. Verify that the engine is in good mechanical condition before continuing with this diagnostic. Refer to «Symptoms - Engine Mechanical»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-1-of-5) .
  4. Ignition OFF for 90 seconds, determine the current vehicle testing altitude.
  5. Ignition ON, observe the scan tool MAP Sensor parameters. Compare the parameter to the «Altitude Versus Barometric Pressure»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-43l-introduction-2-of-2__altitude-versus-barometric-pressure) . The BARO sensor pressure parameter should be within the specified range indicated in the table.
  6. Ignition ON, observe the scan tool MAP and BARO parameters. The MAP and BARO sensor parameters should be within 5 kPa of each other.
  7. Engine running, observe the scan tool MAP Sensor parameter. Slowly increase the engine speed to 2,000 RPM, then allow the engine speed to return to a stable idle. The MAP Sensor parameter should increment to a higher value at 2,000 RPM and then return to near BARO at idle speed.
  8. Engine running, observe the DTC information with a scan tool. DTC P0106 should not set.
  9. 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.
IMPORTANTYou must perform the Circuit/System Verification before proceeding with the circuit/system testing.
  1. Verify the integrity of the entire air induction system by inspecting for the following conditions: Damaged components Loose or improper installation An air flow restriction or leak Any snow or ice build-up in the air cleaner or MAP Sensor
  2. Ignition ON, engine OFF, observe the scan tool BARO parameter. Compare the BARO parameter to the range specified in the Altitude Vs. Barometric Pressure table. Refer to «Altitude Versus Barometric Pressure»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-43l-introduction-2-of-2__altitude-versus-barometric-pressure) . If the BARO parameter is outside the range specified, replace the ECM.
  3. Ignition OFF, disconnect the harness connector at the MAP sensor.
  4. 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.
  5. Ignition ON, test for the 4.8-5.2 volts between the 5-volt reference circuit terminal C 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.
  6. Verify the scan tool MAP parameter is less than 45 kPa. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the ECM.
  7. Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal C. Verify the scan tool MAP parameter is greater than 253 kPa. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  8. If all circuits test normal, test or replace the MAP sensor.
IMPORTANTYou must perform the Circuit/System Testing in order to verify the integrity of the MAF sensor circuits before proceeding with the Component Testing.
  1. Ignition OFF, remove the MAP sensor.
  2. Install a 3A fused jumper wire between the 5-volt reference terminal C and the corresponding terminal of the MAP sensor
  3. Install a jumper wire between the low reference terminal A of the MAP sensor and ground.
  4. Install a jumper wire at the signal terminal B of the MAP sensor.
  5. Connect a DMM between the jumper wire from terminal B of the MAP sensor and ground.
  6. Ignition ON, with the J 23738-A or J 35555 , slowly apply vacuum to the sensor while observing the voltage on the DMM. The voltage should vary between 4.9-0.02 volts, without any spikes or dropouts. If the voltage is erratic, replace the MAP sensor.

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) Regeneration Enable with a scan tool Perform the above to avoid possible soot overloading conditions or possible damage to the DPF.

  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 DPF Regeneration Enable.
  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. «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. Engine running, observe the scan tool MAP and BARO parameters. The MAP and BARO sensor parameters should be within 5 kPa of each other.
  2. Engine running, command the turbocharger Vane Pos. Ctrl. Solenoid valve ON. With a scan tool, slowly increase the engine speed from idle to 2,000 RPM and then return the engine to idle speed. The MAP sensor parameter should increment to a higher value and then return to a near BARO value at idle.
  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.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5-Volt Reference VoltageP0107, P0698, P2564P0107, P0106P0106, P0401, P0699, P2565P0106
MAP Sensor SignalP0107P0107, P0106P0108P0106
Low ReferenceP0107, P0106P0106

DTC P0107 or P0108

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine running at idle, in Park or Neutral Parameter Normal Range: BARO (varies with altitude)
5 volt Reference Voltage43 kPa43 kPa200-205 kPa
MAP Sensor Signal43 kPa43 kPa255 kPa
Low Reference255 kPa

MAP Sensor, kPa

The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by turbocharger output, engine speed, accelerator pedal input, air temperature, and barometric pressure (BARO). A diaphragm within the MAP sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The engine control module (ECM) supplies a regulated 5 volts to the sensor on a 5-volt reference circuit. The ECM supplies a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to the pressure changes, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value. Under normal operation, the lowest pressure that can exist in the intake manifold is equal to BARO. This occurs when the vehicle is operating at idle or when the ignition is ON, while the engine is OFF. The ECM uses the MAP sensor to aid in diagnosis of the turbocharger performance. The highest manifold pressures occur when the turbocharger output is high. Manifold pressure can range from 58 kPa (8 psi) when pressures are low, to greater than 240 kPa (34 psi) when pressures are high, depending on the BARO.

  1. The engine is running for more than 1 second.
  2. The engine speed is between 500-2,500 RPM.
  3. The ignition 1 voltage is more than 11 volts.
  4. The above conditions are met for more than 2 second.
  5. DTC P0107 and P0108 run continuously within the enabling conditions.

P0107

The MAP voltage is less than 10 kPa for 2 seconds.

P0108

The ECM detects that the MAP voltage is greater than 306 kPa for greater than 2 seconds.

  1. DTC P0107 and P0108 are Type A DTCs.
  2. The control module commands Reduced Engine Power mode.
  3. A message center or an indicator may display Reduced Engine Power.

DTC P0107 and P0108 are Type A DTCs.

  1. A wide open throttle (WOT) acceleration from a stop should cause the MAP sensor parameter on the scan tool to increase rapidly.
  2. Verify that any electrical aftermarket devices are properly connected and grounded. Refer to «Checking Aftermarket Accessories»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__checking-aftermarket-accessories) .

Schematic Reference

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)

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

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 Required

J 23738-A Mityvac

J 35555 Metal Mityvac

  1. 1. Verify that DTCs P003A, P0047, P0048, P0234, P0698, P0699, or P2563 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. Determine the current vehicle testing altitude. Ignition ON, observe the scan tool BARO Sensor parameter. Compare the parameter to the Altitude vs. Barometric Pressure table. Refer to «Altitude Versus Barometric Pressure»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-43l-introduction-2-of-2__altitude-versus-barometric-pressure) .
  3. Ignition ON, engine OFF, observe the scan tool MAP Sensor parameter. The MAP Sensor parameters should match the BARO Sensor parameter.
  4. Engine running, observe the scan tool MAP Sensor parameter. Slowly increase the engine speed to 2,000 RPM, then allow the engine speed to return to a stable idle. The MAP Sensor parameter should increment to a higher value at 2,000 RPM and return to near BARO at idle speed.
  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.
  1. Ignition OFF, disconnect the harness connector at the MAP sensor.
  2. Ignition OFF, for 90 seconds, test for less than 5 ohms of resistance between the low reference circuit terminal A and a good 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, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C 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.
  4. Verify the scan tool MAP Sensor parameter is less than 45 kPa. If greater than the specified range, test the signal circuit terminal B 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 B and the 5-volt reference circuit terminal C. Verify the scan tool MAP Sensor parameter is greater than 250 kPa. If less than the specified range, test the sensor 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, test the MAP sensor.
IMPORTANTYou must perform the Circuit/System Testing in order to verify the integrity of the MAP sensor circuits before proceeding with the Component Testing.

Erratic Signal Test

  1. Ignition OFF, disconnect and remove the MAP sensor.
  2. Install a 3A fused jumper wire between the 5-volt reference circuit terminal C and the corresponding terminal C of the MAP sensor.
  3. Install a jumper wire between the low reference terminal A of the MAP sensor and ground.
  4. Install a jumper wire at the signal terminal B of the MAP sensor.
  5. Connect a DMM between the jumper wire from terminal B of the MAP sensor and ground.
  6. Ignition ON, install the J 35555 or J 23738-A to the MAP sensor port. Slowly apply vacuum to the sensor while monitoring the voltage on the DMM. The voltage should vary between 4.9-0.04 volts, without any spikes or dropouts. If the voltage is erratic, replace the MAP sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «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)
  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.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
IAT Sensor 1 SignalP0112P0113P0113P0113
IAT Low Reference

DTC P0112 or P0113

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Ignition ON or Engine Running Parameter Normal Range -39°C to +120°C (-38°F to +248°F)
IAT Sensor 1 Signal149°C (300°F)40°C (-40°F)40°C (-40°F)
IAT Low Reference

IAT Sensor 1

The intake air temperature (IAT) sensor 1 is a variable resistor. The IAT sensor measures the temperature of the air entering the engine. The engine control module (ECM) supplies 5 volts to the IAT signal circuit, and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the IAT signal circuit.

  1. The engine is running.
  2. DTC P0112 and P0113 run continuously.

P0112

The IAT Sensor parameter is greater than 148°C (299°F) for greater than 1 second. This is equal to or less than 0.10 volt on the IAT signal circuit as measured by the ECM.

P0113

The IAT Sensor parameter is less than -39°C (-38°F) for greater than 1 second. This is equal to greater than 4.8 volts on the IAT signal circuit as measured by the ECM.

DTC P0112 and P0113 are Type B DTCs.

DTC P0112 and P0113 are Type B DTCs.

  1. If the engine is cold and the ignition is turned ON, a properly functioning IAT sensor will gradually increment to a higher value. This is due to the heat that is generated by the MAF sensor heating elements.
  2. Depending on the ambient temperature, an IAT sensor signal circuit is shorted to the MAF sensor signal circuit can cause a DTC P0113 to set.
  3. An IAT sensor signal circuit that is shorted to the MAF sensor ignition circuit can cause a DTC P0113 to set.
  4. Verify that any electrical aftermarket devices are properly connected and grounded. Refer to «Checking Aftermarket Accessories»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__checking-aftermarket-accessories) .

Schematic Reference

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

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 IAT Sensor 1 parameter. The reading should be between -39°C to +120°C (-38°F to +248°F) depending on the current ambient temperature and the vehicle operating conditions.
  2. 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 mass air flow MAF/IAT sensor.
  2. Ignition OFF, for 90 seconds, test for less than 5 ohms of resistance between the low reference circuit terminal 4 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, verify the scan tool IAT Sensor 1 parameter is less than -39°C (-38°F). If greater than the specified value, test the signal circuit terminal 5 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 5 and a ground. Verify the scan tool IAT Sensor 1 parameter is greater than 149°C (300°F). If less than the specified value, 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 IAT sensor 1.
  1. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
  2. Measure and record the resistance between the signal terminal 5 and the low reference circuit terminal 4 at the IAT sensor. Compare the value to the Temperature Vs Resistance table. Refer to «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) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Mass Airflow Sensor/Intake Air Temperature 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
  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. «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.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
ECT Sensor SignalP0117P0118P0118P0116, P0128
Low ReferenceP0118P0118P0128

DTC P0116

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine Running Parameter Normal Range: -39 to +120°C (-38 to +248°F)
ECT Sensor Signal150°C (302°F)40°C (-40°F)40°C (-40°F)
Low Reference40°C (-40°F)40°C (-40°F)

ECT Sensor Temperature

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the signal circuit and a ground for the low reference circuit. The ECM uses this high side coolant rationality diagnostic to determine if the input from the ECT sensor is skewed warmer than normal. The internal clock of the ECM will record the amount of time the ignition is OFF. If the calibrated ignition OFF time is met at start-up, the ECM will compare the temperature difference between the ECT and the intake air temperature (IAT) to determine if the temperatures are within an acceptable operating range of each other.

  1. DTCs P0117, P0118, P0182, P0183, P2610, P2184, P2185 are not set.
  2. The engine OFF timer is greater than 10 hours.
  3. The ignition is ON.
  4. The engine run time is greater than 2 seconds.
  5. The start-up IAT is greater than 10°C (50°F).
  6. DTC P0116 runs once per drive cycle within the enabling conditions.

The ECM detects a start-up temperature difference between the ECT sensor and the IAT sensor 2 of more than 15°C (59°F), the vehicle must be driven for more than 360 seconds over 24 km/h (15 mph). If the IAT sensor 2 temperature decreases more than 2.5°C (41.5°F), a block heater is detected and the test is aborted. If the IAT sensor 2 temperature does not decrease, a block heater was not detected and DTC P0116 sets.

DTC P0116 is a Type B DTC.

DTC P0116 is a Type B DTC.

  1. Inspect the ECT sensor terminals for corrosion and for engine coolant leaking through the sensor. Engine coolant that is leaking through the sensor will create a high resistance short to ground. This condition results in less voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a warmer ECT.
  2. This diagnostic runs in a specific range. Measure and record the resistance of the ECT sensor at various ambient temperatures greater than -8°C (+18°F), then compare those measurements to the Temperature vs Resistance table. Refer to «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. An IAT sensor that is skewed colder at various ambient temperatures due to greater resistance than is normal will increase the range between these two sensors. Measure and record the resistance of the IAT sensor at various ambient temperatures, then compare those measurements to the Temperature vs Resistance table. Refer to «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) .
  4. A slight to moderate resistance in the IAT sensor signal circuit or low reference circuit will increase the range between these two sensors. This condition results in a greater voltage on the IAT sensor signal circuit, which is interpreted by the ECM as a colder IAT.

Schematic Reference

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

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)
IMPORTANTThe engine needs to have been OFF for at least 10 hours for the ECT and the IAT sensor 2 to be at ambient temperature. The vehicle should not have changed environments during this time.
  1. Turn OFF the ignition.
  2. Inspect the cooling system surge tank for the proper engine coolant level. Refer to «Cooling System Leak Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing) and «Draining and Filling Cooling System (Static Fill)»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (Vac N Fill)»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system__draining-and-filling-cooling-system-vac) .
  3. If the ignition has been OFF for 10 hours or greater, the ECT and the IAT sensor 2 should be within 15°C (27°F) of each other and also the ambient temperature. Ignition ON, observe the scan tool Start-up ECT and Start-up IAT Sensor 2 parameters. Compare those sensor parameters to each other and also to the ambient temperature to determine if the ECT sensor is skewed warmer.
  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. Ignition OFF, disconnect the harness connector at the ECT sensor.
  2. Ignition OFF for 90 seconds, test for less than 5 ohms 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 control module.
  3. Ignition ON, verify the scan tool ECT parameter is less than -39°C (-40°F). If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the control module.
  4. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool ECT parameter is greater than 149°C (300°F) If less 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 control module.
  5. If all circuits test normal, test or replace the ECT sensor.

Measure and record the resistance of the ECT sensor at various ambient temperatures and compare those measurements to the Temperature vs. Resistance table. Refer to 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) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Engine Coolant Temperature 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 engine control module (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.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
ECT Sensor SignalP0117P0118P0118P011A, P0116, P0128
Low ReferenceP0118P0118P0128

DTC P0117 or P0118

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine Running Parameter Normal Range: -39 to +120°C (-38 to +248°F)
ECT Sensor Signal150°C (302°F)40°C (-40°F)40°C (-40°F)
Low Reference40°C (-40°F)40°C (-40°F)

ECT Sensor Temperature

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit, and a ground for the ECT low reference circuit.

P0117

  1. The ignition is ON.
  2. DTC P0117 runs continuously within the enabling condition.

P0118

  1. The engine has been running for more than 8 minutes.
  2. DTC P0118 runs continuously within the enabling condition.

P0117

The ECM detects that the ECT Sensor parameter is more than 149°C (300°F) for more than 10 seconds. This is equal to less than 0.065 volt on the ECT signal circuit as measured by the ECM.

P0118

The ECT sensor temperature is less than -39°C (-38°F) for more than 10 seconds. This is equal to more than 4.8 volts on the ECT signal circuit, as measured by the ECM.

DTCs P0117 and P0118 are Type B DTCs.

DTCs P0117 and P0118 are Type B DTCs.

An ECT sensor signal circuit or low reference circuit that is shorted to another 5-volt reference circuit can cause a DTC P0118 to set.

Schematic Reference

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

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)
  1. Turn OFF the ignition.
  2. Inspect the cooling system surge tank for the proper engine coolant level. Refer to «Cooling System Leak Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing) and «Draining and Filling Cooling System (Static Fill)»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (Vac N Fill)»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system__draining-and-filling-cooling-system-vac) .
  3. Ignition ON, observe the ECT Sensor parameter. The reading should be between the -39° to +120°C (-38 to +248°F), depending on the current ambient temperature and the vehicle operating conditions.
  4. Use the scan tool to verify the proper operation of the engine cooling system fans.
  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.
  1. Ignition OFF, disconnect the harness connector at the ECT sensor.
  2. Ignition OFF for 90 seconds, test for less than 5 ohms 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 control module.
  3. Ignition ON, verify the scan tool ECT parameter is less than -39°C (-40°F). If greater than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the control module.
  4. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool ECT parameter is greater than 149°C (300°F) If less 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 control module.
  5. If all circuits test normal, test or replace the ECT sensor.

Measure and record the resistance of the ECT sensor at various ambient temperatures and compare those measurements to the Temperature vs. Resistance Table. Refer to 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) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Engine Coolant Temperature 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
  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.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
ECT Sensor SignalP0117P0118P0118P0116, P0128, P011A
Low ReferenceP0118P0118P0128, P011A
ECT Sensor 2 SignalP2185P2184P2184P0116, P0128, P011A
Low ReferenceP2184P2184P0128, P011A

DTC P011A

CircuitShort to GroundOpenShort to Voltage
Parameter Normal Range: -39 to +120°C (-38 to +248°F)
ECT Sensor Signal150°C (302°F)40°C (-40°F)40°C (-40°F)
Low Reference40°C (-40°F)40°C (-40°F)

ECT Sensor Temperature

CircuitShort to GroundOpenShort to Voltage
Parameter Normal Range: -39 to +120°C (-38 to +248°F)
ECT Sensor 2 Signal150°C (302°F)40°C (-40°F)40°C (-40°F)
Low Reference40°C (-40°F)40°C (-40°F)

ECT Sensor 2 Temperature

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the signal circuit and a ground for the low reference circuit. The ECM uses this rationality diagnostic to determine if the input from the ECT or ECT 2 is skewed. The internal clock of the ECM will record the amount of time the ignition is OFF. If the calibration ignition OFF time is met at start-up, the ECM will compare the temperature difference between the ECT and the ECT 2 to determine if the temperatures are within an acceptable operating range of each other.

  1. DTCs P0117, P0118, P0128, P2184, P2105 are not set.
  2. The ignition is ON.
  3. The engine run time is greater than 2 seconds.
  4. The start-up IAT is greater than -30°C (-22°F).
  5. DTC P011A runs continuously within the enabling conditions.

When the ECM detects a temperature difference between the ECT and the ECT sensor 2 of more than 5°C (41°F).

DTC P011A is a Type B DTC.

DTC P011A is a Type B DTC.

  1. Inspect the ECT sensor terminals for corrosion and for engine coolant leaking through the sensor. Engine coolant that is leaking through the sensor will create a high resistance short to ground. This condition results in less voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a warmer ECT.
  2. This diagnostic runs in a specific range. Measure and record the resistance of the ECT sensor at various ambient temperatures greater than -8°C (+18°C), then compare those measurements to the Temperature vs Resistance table. Refer to «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) .

Schematic Reference

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

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)
  1. If the ignition has been OFF for 10 hours or more, the ECT and the ECT sensor 2 should be within 5°C (41°F) of each other, and also the ambient temperature. Turn ON the ignition, with the engine OFF, and use a scan tool to observe the ECT sensor 2 and the ECT sensor parameters. Compare those sensor parameters to each other, and also to the ambient temperature. A compare between ambient temperature and the coolant temperature sensors will determine which ECT is skewed
  2. A quick compare between the ECT and ECT sensor 2 can be made at any time to determine which sensor is skewed.
  3. Inspect the cooling system surge tank for the proper engine coolant level. Refer to «Cooling System Leak Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing) and «Draining and Filling Cooling System (Static Fill)»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (Vac N Fill)»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system__draining-and-filling-cooling-system-vac) .
  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.
IMPORTANTIf you are unable to determine which ECT sensor is skewed, you must perform Circuit/System Verification first.
  1. Ignition OFF, disconnect the harness connector at the affected ECT sensor.
  2. Ignition OFF for 90 seconds, test for less than 5 ohms 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 control module.
  3. Ignition ON, verify the scan tool ECT parameter is less than -39°C (-40°F). If greater than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the control module.
  4. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool ECT parameter is greater than 149°C (300°F) If less 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 control module.
  5. If all circuits test normal, test or replace the ECT sensor.

Measure and record the resistance of the ECT sensor at various ambient temperatures and compare those measurements to the Temperature vs. Resistance table. Refer to 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) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Engine Coolant Temperature 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 engine control module (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.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
ECT Sensor SignalP0117P0118P0118P0116, P0128
Low ReferenceP0118P0118P0128

DTC P0128

CircuitShort to GroundOpenShort to Voltage
Parameter Normal Range: -39 to +149°C (-38 to +300°F)
ECT Sensor Signal150°C (302°F)40°C (-40°F)40°C (-40°F)
Low Reference40°C (-40°F)40°C (-40°F)

ECT Sensor Temperature

The engine control module (ECM) uses this diagnostic to determine if the engine coolant temperature (ECT) has reached the minimum calibrated thermostat regulating temperature. The ECM supplies 5 volts to the ECT signal circuit, and a ground for the ECT low reference circuit. The ECM monitors the temperature of the coolant by using the input received from the ECT sensor. The ECM calculates the amount of fuel burned since start-up to determine if the vehicle has been driven within the conditions that would allow the engine coolant to heat up normally to the thermostat regulating temperature. If the coolant temperature does not increase normally, or does not reach the regulating temperature of the thermostat, the engine is considered not warm enough for stable, low emission operation.

The purpose of this rationality diagnostics is to use the ECT sensor to determine if the engine coolant will heat up at the correct rate, and also meet the calibrated target temperatures under various operating conditions.

The ECM uses the start-up ECT and the start-up intake air temperature (IAT) to begin the diagnostic calculation.

  1. DTC P0112, P0113, P0116, P0117, P0118 are not set.
  2. The engine is running.
  3. The IAT 1 is less than 10°C (50°F), low region.
  4. The IAT 1 is greater than 10°C (50°F), high region.
  5. The start-up engine coolant temperature is less than 65°C (149°F).
  6. DTC P0128 will only run once per ignition cycle until a Pass, Fail or Disable condition exists.

The engine did not meet the ECT target temperatures of 50°C (120°F) low region or 72°C (162°F) high region during expected calibrated warm-up times and start-up temperatures.

DTC P0128 is a Type B DTC.

DTC P0128 is a Type B DTC.

DTC P0128 is designed to detect for a stuck open thermostat.

Schematic Reference

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

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)
CAUTIONUnder pressure, the temperature of the solution in the radiator can be considerably higher, without boiling. Removing the radiator cap while the engine is hot (pressure is high), will cause the solution to boil instantaneously, with explosive force. The solution will spew out over the engine, fenders, and the person removing the cap. Serious bodily injury may result. Flammable antifreeze, such as alcohol, is not recommended for use at any time. Flammable antifreeze could cause a serious fire.
IMPORTANTA critical analysis of the operation of the thermostat is necessary to properly diagnose this DTC.
  1. Verify the proper heat range and for a stuck open thermostat. Refer to «Thermostat Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
  2. Inspect the cooling system surge tank for the proper engine coolant level. Refer to «Cooling System Leak Testing»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing) and «Draining and Filling Cooling System (Static Fill)»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (Vac N Fill)»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system__draining-and-filling-cooling-system-vac) .
  3. Inspect the ECT sensor terminals for corrosion and for engine coolant leaking through the sensor.
  4. Verify the proper operation of the engine cooling fan, fan stuck ON/fully engaged all the time.
  5. Engine running, observe the DTC information with a scan tool. DTC P0128 should not set.
  6. 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 ECT sensor.
  2. Ignition OFF, test for less than 5 ohms 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 control module.
  3. Ignition ON, verify the scan tool ECT parameter is less than -39°C (-40°F). If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the control module.
  4. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool ECT parameter is greater than 149°C (300°F) If less 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 control module.
  5. If all circuits test normal, test or replace the ECT sensor.
  1. Measure and record the resistance of the ECT sensor at various ambient temperatures and compare those measurements to the Temperature vs. Resistance table. Refer to «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) .
  2. Refer to «Thermostat Diagnosis»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Thermostat Replacement (4.3L)»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Thermostat Replacement (6.6L (LLY, LBZ))»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «Thermostat Replacement (6.6L (LMM))»(/chevrolet/chevy-express-h1500/2003-2012/remont/cooling-system-mechanical/#engine-cooling-system)
  2. «Engine Coolant Temperature 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.

Fuel is drawn from the fuel tank through the fuel heater, then to the fuel injection pump. Fuel temperature is monitored by the fuel temperature sensor, which is located in the fuel return line on the engine. The engine control module (ECM) supplies 5 volts and a ground circuit to the sensor. A fuel cooler located in front of the fuel tank is used to help keep the fuel temperature at an acceptable limit. When the ECM detects a fuel temperature above the pre-determined value, this diagnostic will fail, but will not turn the malfunction indicator lamp (MIL) ON.

  1. The ignition is ON.
  2. DTC P0168 runs continuously within the enabling conditions.
  1. The fuel temperature sensor is above 122°C (252°F) for more than 5 seconds.
  2. DTC P0181, P0182 or P0183 are not set.

DTC P0168 is a Type C DTC.

DTC P0168 is a Type C DTC.

Schematic Reference

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

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 Fuel Temperature and ECT Temperature parameters should closely match each other when the engine has not been started and soaked overnight.
  2. Engine running, observe the DTC information with a scan tool. DTC P0168 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.
IMPORTANTFuel temperature overheating may be cause by a fuel heater element that is stuck on. Refer to Fuel Heater Always On .
  1. With ignition ON and the engine OFF, observe the Fuel Temperature and ECT Temperature parameters with a scan tool. If the temperatures do not closely match each other when the engine has cold soaked overnight, test for a skewed fuel temperature sensor. Refer to Component Testing in the diagnostic.
  2. Inspect for debris or damage to the cooling fins of the fuel cooler. If a damaged fuel cooler was found, repair or replace the cooler.
  1. Remove the fuel temperature sensor from the engine.
  2. Measure the resistance of the sensor at different ambient temperatures and record results. Compare the results to the Temperatures vs. Resistance Fuel Temperature table. Refer to «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) . If the fuel temperature sensor is skewed, replace the sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Temperature Sensor Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-introduction-2-of-2)
  2. «Fuel Cooler 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 fuel temperature sensor is a thermistor. The engine control module (ECM) supplies the fuel temperature sensor a bias voltage of 5 volts on the signal circuit and also provides a low reference circuit to the sensor. When the fuel temperature sensor is cold, the resistance is high. The fuel temperature sensor signal voltage remains near the bias voltage cold and decreases as the sensor warms. The control module monitors the fuel temperature sensor signal circuit in order to calculate the temperature of the fuel entering the engine.

  1. DTCs P0182 and P0183 are not set.
  2. The ignition must be turned OFF for 10 hours or longer.
  3. The intake air temperature (IAT) sensor 1 is more than 10°C (50°F) at start-up.
  4. DTC P0181 will only run once per ignition cycle until a Pass, Fail, or Disable conditions exists.
  1. The fuel temperature and the IAT 1 are more than 100°C (180°F) of each other at start-up. OR
  2. The fuel temperature and the IAT 1 are more than 10°C (18°F) of each other at start-up. AND
  3. The IAT has dropped more than 2.5°C (4.5°F) after running more than 6 minutes above 24 km/h (15 mph).

DTC P0181 is a Type C DTC.

  1. DTC P0181 is a Type C DTC.
  2. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
  3. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
  4. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
  5. Clear the MIL and the DTC with a scan tool.

Schematic Reference

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)
IMPORTANTIf DTC P0182, P0183, or P2199 are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle . If you cannot duplicate the condition, 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/Failure Records.
  1. Turn ON the ignition and observe the Fuel Temperature Sensor parameter with a scan tool. The fuel temperature parameter should be within -30 to +120°C (-22 to +248°F).
  2. Engine running, observe the DTC information with a scan tool. DTC P0181 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. Disconnect the fuel temperature sensor.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the Fuel Temperature parameter with a scan tool. If the fuel temperature is less than -39°C (-38.2°F), test the signal circuit for an open or high resistance.
  4. Connect a 3A fused jumper wire between the fuel temperature sensor signal circuit and the low reference circuit. If the fuel temperature is less than 120°C (248°F), test for high resistance in the signal circuit or the low reference circuit.
  5. If all circuits test normal, refer to Component Testing in this diagnostic.
  1. Disconnect the fuel temperature sensor and measure the resistance of the sensor with a DMM.
  2. Record the values at various fuel temperatures and compare those results 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) (Fuel Temperature). If the sensor does not closely match through the temperature ranges, replace the fuel temperature sensor.

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.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
Fuel Temperature SignalP0182P0183 2P0183P0183
Low Reference2P01831
1 Opens fuse in 12-volt circuit 2 Temperature is skewed and may not have any codes

DTC P0182 or P0183

CircuitShort to GroundHigh ResistanceOpenShort to Voltage
Operating Conditions: The Ignition ON, with the Engine OFF Parameter Normal Range: -30 to +120°C (-22 to +248°F)
Fuel Temperature Signal120°C (248°F)Varies 140°C (-40°F)40°C (-40°F)
1 Skewed sensor

Fuel Temperature Sensor

The fuel temperature sensor is a thermistor. The engine control module (ECM) supplies the fuel temperature sensor a bias voltage of 5 volts on the signal circuit and also provides a low reference circuit to the sensor. When the fuel temperature sensor is cold, the resistance is high. The fuel temperature sensor signal voltage remains near the bias voltage cold and decreases as the sensor warms. The control module monitors the fuel temperature sensor signal circuit in order to calculate the temperature of the fuel entering the engine.

P0182

  1. The ignition is ON.
  2. DTC P0182 runs continuously within the enabling conditions.

P0183

  1. The ignition is ON.
  2. DTC P0183 runs continuously within the above enabling conditions.

P0182

The fuel temperature sensor is more than 120°C (248°F) for 2 seconds.

P0183

The fuel temperature sensor is less than -30°C (-22°F) for 2 seconds.

DTCs P0182 and P0183 are Type A DTCs.

DTCs P0182 and P0183 are Type A DTCs.

  1. A short to a separate 5-volt source may set a DTC P0183.
  2. A skewed sensor could result in poor driveability concerns.

Schematic Reference

Connector End View Reference

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. «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)

DTC Type Reference

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)
IMPORTANTIf you cannot duplicate the condition, 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/Failure Records.
  1. Turn ON the ignition and observe the Fuel Temperature Sensor parameter with a scan tool. The fuel temperature parameter should be within the operating range.
  2. Engine running, observe the DTC information with a scan tool. DTCs P0182 or P0183 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.

P0182

  1. Turn OFF the ignition for 30 seconds or until the ECM powers down.
  2. Disconnect the fuel temperature sensor.
  3. Turn ON the ignition, with the engine OFF and observe the fuel temperature sensor parameter with a scan tool. Fuel temperature should go to -40°C (-40°F). If the fuel temperature is warmer than -40°C (-40°F), test the signal circuit for a short to ground, a short to any low reference circuits. If the circuits test normal, replace the control module.
  4. If all circuits test normal, replace the fuel temperature sensor.

P0183

  1. Turn ON the ignition, with the engine OFF and observe the fuel temperature sensor parameter with a scan tool. If the fuel temperature is colder than -30°C (-22°F), test the low reference circuit for an open. If the circuits test normal, replace the control module.
  2. Disconnect the fuel temperature sensor connector.
  3. Using a DMM, measure the voltage between the fuel temperature signal circuit and a ground. If the voltage measures more than 5.2 volts, test the signal circuit for a short to voltage. If the circuits test normal, replace the control module.
  4. Connect a 3A fused jumper between the signal circuit of the fuel temperature sensor and the low reference circuit.
  5. Observe the fuel temperature sensor parameter with a scan tool. If temperature is colder than 120°C (248°F), test the signal circuit for an open, high resistance or a faulty ECM.
  6. With the ignition still turned ON, connect a DMM between the signal circuit and a ground.
  7. With the DMM set to the mA scale, measure the current. If the current measures more than 15 mA, test the signal circuit for a short to a 5-volt reference circuit. If the circuits test normal, replace the control module.
  8. If all circuits test normal, replace the fuel temperature sensor.
  1. Disconnect the fuel temperature sensor and measure the resistance of the sensor with a DMM.
  2. Record the values at varies engine temperatures and compare those results to the Temperature vs. Resistance Fuel Temperature table. Refer to «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) . If the sensor does not closely match through the temperature ranges, replace the fuel temperature sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Temperature 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
  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.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
FRP SignalP0192P0088, P0191P0193P0193
FRP Low ReferenceP0191P01931
FRP 5-Volt ReferenceP0117, P0462, P0522, P0652P0087, P0191P0193P0118, P0653
Fuel Pressure Regulator Solenoid Supply VoltageP0088, P0090P0088P0090P0087, P0191, P2510
1 Opens circuit fuse or opens circuit.

DTC P0191

CircuitShort to GroundHigh ResistanceOpenShort to Voltage
Operating Conditions: The Ignition ON, with the Engine OFF Parameter Normal Range: 0.352-0.650 volt
5-Volt Reference0 MPa (0 psi)Varies 1200 MPa (29,000 psi)0 MPa (0.0 psi)
FRP Sensor Signal0 MPa (0 psi)Varies 1200 MPa (29,000 psi)200 MPa (29,000 psi)
FRP Sensor Low ReferenceVaries 1200 MPa (29,000 psi)2
Fuel Pressure Regulator Solenoid Supply Voltage0.2 MPa (34.8 psi) 171 MPa (10,300 psi) 10.2 MPa (34.8 psi) 10.2 MPa (34.8 psi) 1
1 Fuel pressure erratic 2 Opens circuit fuse or opens circuit

Actual Fuel Rail Pressure

The fuel rail pressure (FRP) sensor has a 5-volt reference circuit, a signal circuit, and a low reference circuit. The engine control module (ECM) monitors the voltage on the FRP sensor circuits. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low. The fuel pressure regulator has a solenoid supply voltage circuit and a solenoid control circuit. The ECM controls the fuel pressure regulator, which regulates high pressure fuel that goes to the fuel injector rails and the injectors.

  1. DTCs P0016, P062F, P0116, P0117, P0118, P0192, P0193, P0652 or P0653 are not set.
  2. The ignition is ON, with the engine OFF for 30 seconds.
  3. The coolant temperature has dropped more than 5°C (9°F) since Last Key Cycle.
  4. The FRP sensor voltage is between 352-650 volts. OR
  5. The ignition has been off less than 70 seconds.
  6. The fuel temperature is more than 60°C (140°F).
  7. The FRP sensor voltage is between 352-650 volts.
  8. This diagnostic runs continuously within the above conditions.
  1. The FRP sensor is below 0.352 volt or above 0.650 volt when the ignition is ON and the engine is OFF. OR
  2. The FRP sensor is below 0.352 volt or above 0.650 volt within 70 seconds of the ignition being turned OFF.

DTC P0191 is a Type A DTC.

DTC P0191 is a Type A DTC.

Schematic Reference

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

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)
IMPORTANTYou must perform the Circuit/System Verification before proceeding with Circuit/System Testing. If you cannot duplicate the condition, 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/Failure Records.
  1. Verify that DTCs P0652 or P0653 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. Observe the Fuel Rail Pressure Sensor parameter with a scan tool. During engine cranking, the pressure should be at least 10 MPa. With the engine running at idle, the pressure should be close to the Desired Fuel Rail Pressure. As the engine speed increases, the Desired Fuel Rail Pressure and the Actual Fuel Rail Pressure should closely match each other.
  3. Engine running, observe the DTC information with a scan tool. DTC P0191 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.
IMPORTANTFuel pressure control will be disable if DTC P0087, P0088, P0192, or P0193 are set. Codes must be cleared to enable the device control.
  1. Turn OFF the ignition.
  2. Disconnect the ECM connector and the fuel pressure regulator connector.
  3. Test the fuel pressure regulator solenoid supply voltage circuit for a short to voltage.
  4. Disconnect the FRP sensor.
  5. Test the FRP signal circuit, the 5-volt reference circuit, and the low reference circuit for high resistance. If all circuits test normal, replace the FRP sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Injection Fuel Rail Fuel Pressure 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, 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) provides an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
FRP SignalP0192P0088, P0191P0193P0193
FRP Low ReferenceP0191P01931
FRP 5-Volt ReferenceP0117, P0462, P0522, P0652P0087, P0191P0193P0118, P0653
Fuel Pressure Regulator Solenoid Supply VoltageP0088, P0090P0088P0090P0087, P0191, P2510
1 Opens circuit fuse or opens circuit.

DTC P0192 or P0193

CircuitShort to GroundHigh ResistanceOpenShort to Voltage
Operating Conditions: The Ignition ON, with the Engine OFF Parameter Normal Range: 0.352-0.650 volt
5-Volt Reference0 MPa (0 psi)Varies 1200 MPa (29,000 psi)0 MPa (0.0 psi)
FRP Sensor Signal0 MPa (0 psi)Varies 1200 MPa (29,000 psi)200 MPa (29,000 psi)
FRP Sensor Low ReferenceVaries 1200 MPa (29,000 psi)2
Fuel Pressure Regulator Solenoid Supply Voltage0.2 MPa (34.8 psi) 171 MPa (10,300 psi) 10.2 MPa (34.8 psi) 10.2 MPa (34.8 psi) 1
1 Fuel pressure erratic 2 Opens circuit fuse or opens circuit

Actual Fuel Rail Pressure

The fuel rail pressure (FRP) sensor has a 5-volt reference circuit, a signal circuit, and a low reference circuit. The engine control module (ECM) monitors the voltage on the FRP sensor circuits. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low. The fuel pressure regulator has a solenoid supply voltage circuit and a solenoid control circuit. The ECM controls the fuel pressure regulator, which regulates high pressure fuel that goes to the fuel injector rails and the injectors.

  1. The ignition is ON.
  2. DTCs P0652 or P0653 are not set.
  3. These diagnostics run continuously within the enabling conditions.

P0192

The ECM detects the signal circuit voltage that is less than 0.254 volts for more than one second.

P0193

The ECM detects that the signal circuit voltage is more than 4.75 volts for more than one second.

  1. DTCs P0192 and P0193 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.

DTCs P0192 and P0193 are Type A DTCs.

Schematic Reference

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

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)
IMPORTANTYou must perform the Circuit/System Verification before proceeding with Circuit/System Testing. If you cannot duplicate the condition, 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/Failure Records.
  1. Verify that DTCs P0652 or P0653 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. Observe the Fuel Rail Pressure Sensor parameter with a scan tool. During engine cranking, the pressure should be at least 10 MPa. With the engine running at idle, the pressure should be close to the Desired Fuel Rail Pressure. As the engine speed increases, the Desired Fuel Rail Pressure and the Fuel Rail Pressure Sensor should closely match each other.
  3. Engine running, observe the DTC information with a scan tool. DTCs P0192 or P0193 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.
IMPORTANTFuel pressure control will be disable if DTC P0087, P0088, P0192, or P0193 are set. Codes must be cleared to enable the device control.
  1. Ignition OFF, disconnect the FRP sensor connector.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the Fuel Rail Pressure Sensor parameter with a scan tool The fuel pressure should be 200 MPa (29,000 psi). If the fuel pressure is 0 MPa (0 psi), test the FRP sensor signal circuit for a sort to ground. If the circuit tests normal, replace the FRP sensor.
  4. Probe the signal circuit with a test lamp connected to ground. The test lamp should not illuminate. If the test lamp illuminates, test the signal circuit for a short to voltage.
  5. Connect a fused jumper between the FRP signal circuit and the low reference circuit and observe the Fuel Rail Pressure Sensor parameter with a scan tool. The fuel pressure should be 0 MPa (0 psi). If the fuel pressure does not go to 0 MPa (0 psi), test the FRP sensor signal circuit and the low reference circuit for an open. If the circuit tests normal, replace the FRP sensor.
  6. Connect a DMM between the FRP 5-volt reference circuit and ground, and measure the voltage. The voltage should be 4.8-5.2 volts. If the voltage is not within the specified range, test for an open in the 5-volt reference circuit.
  7. If all circuits test normal, replace the control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Injection Fuel Rail Fuel Pressure 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, 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) provides an overview of each diagnostic category.
Fuel Injector CircuitsShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
Fuel Injector Positive Voltage Control Group 1P2146P2146P0201, P0204 1P1233, P1224, P2146
Fuel Injector Positive Voltage Control Group 2P2149P2149P0206, P0207 1P1239, P1242, P2149
Fuel Injector Positive Voltage Control Group 3P2152P2152P0202, P0205 1P1227, P1236, P2152
Fuel Injector Positive Voltage Control Group 4P2155P2155P0203, P0208 1P122A, P1247, P2155
Fuel Injector 1 ControlP1233, P2146P2146P0201P1224, P2146
Fuel Injector 2 ControlP1236, P2152P2152P0202P1227, P2152
Fuel Injector 3 ControlP1247, P2155P2155P0203P122A, P2155
Fuel Injector 4 ControlP1224, P2146P2146P0204P1233, P2146
Fuel Injector 5 ControlP1227, P2152P2152P0205P1236, P2152
Fuel Injector 6 ControlP1242, P2149P2149P0206P1239, P2149
Fuel Injector 7 ControlP1239, P2149P2149P0207P1242, P2149
Fuel Injector 8 ControlP122A, P2155P2155P0208P1247, P2155
1 Misfire DTCs may also set.

DTC P0201, P0202, P0203, P0204, P0205, P0206, P0207, or P0208

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 P0201, P0202, P0203, P0204, P0205, P0206, P0207, and P0208 are Type A DTCs.

DTCs P0201, P0202, P0203, P0204, P0205, P0206, P0207, and P0208 are Type A DTCs.

Schematic Reference

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

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)
IMPORTANTIf you cannot duplicate the condition, 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/Failure Records.

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. Test the affected fuel injector control circuit for an open between the ECM and the fuel injector.
  2. Test the affected fuel injector for high resistance. Refer to Component Testing in this diagnostic. If the circuit and fuel injector test normal, replace the ECM.

Two or More Fuel Injector DTCs Set

  1. Test the affected fuel injector circuit for an following: An open between the ignition position voltage control circuit splice and the fuel injector connector An open between the ECM and the ignition positive voltage control circuit splice
  2. Test the affected fuel injector for high resistance. Refer to Component Testing in this diagnostic. If the circuit and fuel injector test 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) provides an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to Voltage
Fuel Pump Relay ControlP0230 31P0230 3P0230 2
Fuel Pump Relay GroundP0230P02303
Fuel Pump Relay Battery Voltage3132
Fuel Pump Supply Voltage3132
Fuel Pump Ground133
1 Low current, fuel pump runs slow 2 Pump operates continuously, then discharges battery 3 Pump inoperative

DTC P0230

An electric fuel pump is used to prime the fuel system after changing the fuel filter or servicing the fuel system. The fuel pump is part of the diesel fuel conditioning module (DFCM) assembly. The fuel pump is powered by the fuel pump relay. The fuel pump relay is controlled by the engine control module (ECM). The ECM enables the fuel pump when the ignition is turn on and will continue to run for 2 minutes or until the engine starts. If the engine does not start due to low fuel pressure and the ignition is left in the on position, the pump will run for up to 2 minutes or until the ignition is turned off. The ECM will also turn off the fuel pump if incorrect voltage is detected on the control circuit. The ECM will need to be powered down with a key cycle during diagnosis or after repairs, before it will command the fuel pump on again.

Ignition is ON.

  1. The ECM detects an incorrect voltage on the control circuit of the fuel pump relay.
  2. The above condition exists for 1 second.

DTC P0230 is a type C DTC.

DTC P0230 is a type C DTC.

Schematic Reference

Connector End View Reference

  1. «Inline Harness Connector End Views»(/chevrolet/chevy-express-h1500/2003-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-starting-point-and-in-line-harness-connector-end-views)
  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

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 Required

  1. CH-48027 Digital Pressure Gage
  2. J 43244 Relay Puller Pliers
  1. Install the CH-48027 to the fuel system service port on the right from side of the engine. Command the fuel pump on, using a scan tool and observe the fuel pressure gage. Fuel pressure should be a minimum of 69 kPa (10 psi) with the fuel pump running.
  2. Engine running, observe the DTC information with a scan tool. DTC P0230 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.
  2. Remove the fuel pump relay and turn ON the ignition, with the engine OFF.
  3. Probe the control circuit of the fuel pump relay with a test lamp that is connected to a good ground.
  4. Command the fuel pump ON and OFF with a scan tool. If the test lamp remains illuminated, test the fuel pump relay control circuit for a short to voltage or a faulty ECM. If the test lamp does not turn ON and OFF with each command, test the fuel pump relay control circuit for a short to ground or an open. If the circuit tests normal replace the control module.
  5. Connect a test lamp between the control circuit of the fuel pump relay and the ground circuit of the relay.
  6. Command the fuel pump ON and OFF with a scan tool. If the test lamp does not turn ON and OFF with each command, test the fuel pump relay ground circuit for an open or high resistance. If the test lamp turns ON and OFF with each command, replace the fuel pump relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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 manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by turbocharger output, engine speed, accelerator pedal input, ambient air temperature, and barometric pressure (BARO). A diaphragm within the MAP pressure sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates these changes into electrical resistance. The MAP pressure sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts on the 5-volt reference circuit and a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to boost pressures, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value. Under normal operation, the lowest pressure that can exist in the intake manifold is equal to the BARO. This occurs when the vehicle is operated at idle or when the ignition is ON while the engine is OFF. The highest manifold pressures occur when the turbocharger output is high. Manifold pressure can range from 58 kPa (8 psi) when pressures are low to more than 240 kPa (34 psi) when pressures are high, depending on the BARO. The MAP pressure sensor has a range of 33-255 kPa (4-36 psi). The ECM diagnoses boost pressures by a calculated predicted value at a predetermined engine load and speed. The ECM then compares the predicted value to the sensor actual input.

  1. DTC P0106, P0563, P2564 or P2565 is not set.
  2. The engine speed is between 800-3,600 RPM.
  3. DTC P0234 runs continuously when the above conditions are met.

The measured boost pressure is greater than 39 kPa above the expected range for 10 seconds.

  1. DTC P0234 is a Type A DTC.
  2. The control module commands the Engine control system to operate in Reduced Engine Power Mode.
  3. A message center or an indicator may display Reduced Engine Power.
  4. Regeneration is inhibited.

DTC P0234 is a Type A DTC.

Schematic Reference

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)

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

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. 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) .
  2. Engine running at idle; observe the scan tool MAP and BARO parameters. The reading should be within 1-10 kPa of each other.
  3. Engine running, observe the DTC information with a scan tool. DTC P0234 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. Verify the integrity of the air induction system and the turbocharger system by inspecting for restrictions or leaks.
  2. Engine running, command the TC Vane Pos. Ctrl. Solenoid ON, while performing a snapshot of the induction data list. Perform the following actions during the snapshot: Refer to «Scan Tool Snapshot Procedure»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__scan-tool-snapshot-procedure) . Slowly increase the engine speed to 1,700 RPM for 5 seconds, and then slowly return the engine speed to a stable idle. Plot the snapshot and verify that the MAP sensor parameter increases smoothly and follows the Engine Speed parameter through-out the entire engine speed range. If the MAP parameter did not change smoothly or did not follow the Engine Speed parameter, inspect the turbocharger and turbocharger ducts for debris, damage, or sticking vanes. Refer to «Turbocharger Cleaning and Inspection»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-4-of-5__turbocharger-cleaning-and-inspection) .
  3. If the turbocharger inspections are normal, replace the MAP sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Turbocharger Replacement (LLY, LBZ)»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-2-of-5__turbocharger-replacement-lly-lbz) or «Turbocharger Replacement (LMM)»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-2-of-5__turbocharger-replacement-lmm)
  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. «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 manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by turbocharger output, engine speed, accelerator pedal input, ambient air temperature, and barometric pressure (BARO). A diaphragm within the MAP pressure sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates these changes into electrical resistance. The MAP pressure sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts on the 5-volt reference circuit and a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to pressures, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value. Under normal operation, the lowest pressure that can exist in the intake manifold is equal to the BARO. This occurs when the vehicle is operated at idle or when the ignition is ON while the engine is OFF. The highest manifold pressures occur when the turbocharger output is high. Manifold pressure can range from 58 kPa (8 psi) when pressures are low to more than 240 kPa (34 psi) when pressures are high, depending on the BARO. The MAP pressure sensor has a range of 33-255 kPa (4-36 psi). The ECM monitors the MAP sensor by comparing a calculated predicted value at a predetermined engine load and speed, to the actual sensor input.

  1. DTC P2564 or P2565 is not set.
  2. The engine speed is between 800-3,000 RPM.
  3. DTC P0299 runs continuously when the above conditions are met.

The measured MAP pressure is more than 39 kPa below the expected range for 10 seconds.

  1. DTC P0299 is a Type A DTC.
  2. A message center or an indicator may display reduced engine power.
  3. The control module commands reduced engine power.

DTC P0299 is a Type A DTC.

  1. If the condition is intermittent. 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) and «Inducing Intermittent Fault Conditions»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis) .
  2. A MAP sensor that is stuck at BARO, or is skewed 40 kPa lower than desired while under boost will cause this DTC to set.
  3. 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.

Schematic Reference

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)

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

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, P046C, P0402, P0403, P0698, P0699, P2563, P2564 or P2565 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. Engine running, command the TC Vane Pos. Ctrl. Solenoid ON, while performing a snapshot of the induction data list. Perform the following actions during the snapshot: Refer to «Scan Tool Snapshot Procedure»(/chevrolet/chevy-express-h1500/2003-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-troubleshooting-diagnosis__scan-tool-snapshot-procedure) . Slowly increase the engine speed to 1,700 RPM for 5 seconds and then return the engine speed to idle. Plot the snapshot and verify that the MAP sensor parameter increases smoothly and follows the Engine Speed parameter as the engine speed is increased, and then returned to idle If the MAP parameter plot slope is not a straight line with even the RPM change, replace the MAP sensor.
  3. Engine running, observe the DTC information with a scan tool. DTC P0299 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. Verify the integrity of the air induction system, the turbocharger ducts and hoses by inspecting for the following conditions: Any damaged components Any loose or improperly installed components Any wet or restricted air filter Any exhaust leaks before the turbocharger Any exhaust restrictions after the turbocharger Any snow or ice build-up in cold climates at the air cleaner and MAP sensor
  2. Test the charge air cooler for leaks. Refer to «Charge Air Cooler Diagnosis (Charge Air Cooler Air Leak Test)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lmm-troubleshooting-diagnosis) «Charge Air Cooler Diagnosis (Full System Air Leak Test)»(/chevrolet/chevy-express-h1500/2003-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-66l-lbz-and-lly-troubleshooting-diagnosis) .
  3. Test the turbocharger oil supply feed. Refer to «Turbocharger Lack of Oil Supply»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-1-of-5__turbocharger-lack-of-oil-supply) .
  4. Inspect the turbocharger oil supply tube for restrictions. If a restriction is found, clean or replace the oil supply tube as necessary.
  5. Inspect the turbocharger for debris, worn impeller and turbine blades, or damage Refer to «Turbocharger Cleaning and Inspection»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-4-of-5__turbocharger-cleaning-and-inspection) . If worn or damaged turbocharger blades or vanes are found, replace the turbocharger assembly.
  6. If the induction system, charger air cooler system, the turbocharger, and the turbocharger oil supply test normal, replace the MAP sensor.

If any service has been performed on the turbocharger or on the turbocharger components, a turbocharger relearn must be performed. Failure to perform the turbocharger learn procedure may cause this DTC to set. Refer to Turbocharger Learn .

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.

  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 exhaust particulate cleaning
  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 Replacement (LLY, LBZ)»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-2-of-5__turbocharger-replacement-lly-lbz) or «Turbocharger Replacement (LMM)»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-2-of-5__turbocharger-replacement-lmm)
  4. «Turbocharger Oil Feed Pipe Replacement»(/chevrolet/chevy-express-h1500/2003-2012/remont/mechanical/#engine-mechanical-66l-2-of-5)

Engine running, command the TC Vane Pos. Ctrl. Solenoid ON, while performing a snapshot of the induction data list. Perform the following actions during the snapshot: Refer to Scan Tool Snapshot Procedure .

  1. Slowly increase the engine speed to 1,700 RPM for 5 seconds and then return the engine speed to idle.
  2. Plot the snapshot and verify that the MAP sensor parameter increases smoothly and follows the Engine Speed parameter as the engine speed is increased, and then returned to idle.

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Engine Controls Schematics
• Powertrain Diagnostic Trouble Code (DTC) Type Definitions
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Diagnostic Repair Verification
• Engine Front Cover Replacement
• Camshaft Replacement
• Turbocharger Learn
• Scan Tool Data List (Engine Control Module)
• Scan Tool Data List (Glow Plug Control Module)
• Scan Tool Data Definitions
• Scan Tool Output Controls
• Diagnostic Trouble Code (DTC) List - Vehicle
• Turbocharger Cleaning and Inspection
• Turbocharger Replacement (LLY, LBZ)
• Turbocharger Replacement (LMM)
• Control Module References
• Contaminants-in-Fuel Diagnosis
• Fastener Tightening Specifications
• Engine Cranks but Does Not Run
• 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)
• Road Test Caution
• Restricted Exhaust
• Exhaust Leakage
• Charge Air Cooler Diagnosis (Full System Air Leak Test)
• Exhaust Gas Recirculation and Cooler Removal
• Checking Aftermarket Accessories
• DTC P0698 or P0699
• Symptoms - Engine Mechanical
• Altitude Versus Barometric Pressure
• Cooling System Leak Testing
• Draining and Filling Cooling System (Static Fill)
• Draining and Filling Cooling System (Vac N Fill)
• Fuel Injector Replacement (Right)
• Fuel Injector Replacement (Left)
• Inline Harness Connector End Views
• Scan Tool Snapshot Procedure
• Inducing Intermittent Fault Conditions
• Turbocharger Lack of Oil Supply

More articles — Engine Performance