Engine Controls - 2.0l - (Introduction) Chevrolet Cobalt I

Temperature vs Resistance

Temperature vs Resistance

Altitude vs Barometric Pressure

Altitude vs Barometric Pressure

Ignition System Specifications

Ignition System Specifications

Fastener Tightening Specifications

Fastener Tightening Specifications

Emissions Related DTCs

Action Taken When the DTC Sets - Type A

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

Action Taken When the DTC Sets - Type B

1. The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC - Type A or Type B

1. The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC Last Test Failed clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Use a scan tool in order to clear the MIL and the DTC.

Non-Emissions Related DTCs

Action Taken When the DTC Sets - Type C

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The MIL will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

Action Taken When the DTC Sets - Type D

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The MIL will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.

Conditions for Clearing the DTC - Type C or Type D

1. A last test failed, or current DTC, clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Use a scan tool in order to clear the DTC.

Diagnostic Trouble Code (DTC) Type(s)

Diagnostic Trouble Code (DTC) Type(s)

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Engine Controls Schematic Icons

Engine Controls Schematic Icons Icon Icon Definition NOTE: The OBD II symbol is used on the circuit diagrams in order to alert the technician that the circuit is essential for proper OBD II emission control circuit operation. Any circuit which fails and causes the malfunction indicator lamp (MIL) to turn ON, or causes emissions-related component damage, is identified as an OBD II circuit. IMPORTANT: Twisted-pair wires provide an effective shield that helps protect sensitive electronic components from electrical interference. If the wires were covered with shielding, install new shielding. In order to prevent electrical interference from degrading the performance of the connected components, you must maintain the proper specification when making any repairs to the twisted-pair wires shown : The wires must be twisted a minimum of 9 turns per 31 cm (12 in) as measured anywhere along the length of the wires The outside diameter of the twisted wires must not exceed 6.0 mm (0.25 in)

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Powertrain Control Module (PCM) Connector End Views

Powertrain Control Module (PCM) C1 Connector Part Information OEM: 15452125 Service: See Catalog 56-Way F Micro 64 Sealed (BU) Pin Wire Color Circuit No. Function 1 TN/BK 2500 High Speed GMLAN Serial Data (+) (1) 2 TN 2501 High Speed GMLAN Serial Data (-) (1) 3-5 - - Not Used 6 D-GN/WH 459 A/C Compressor Clutch Relay Control 7 BN 1271 Accelerator Pedal Position Low Reference (1) 8 PU 1272 Accelerator Pedal Position Low Reference (2) 9 - - Not Used 10 D-BU 473 High Speed Cooling Fan Relay Control 11 - - Not Used 12 PU 1589 Primary Fuel Level Sensor Signal 13 PK/BK 5293 Engine Main Relay Fused Control (4) 14 L-BU 6118 Manifold Air Temperature Sensor Signal 15 - - Not Used 16 D-GN 1049 ECM/PCM/VCM Class 2 Serial Data 17 GY 2700 A/C Pressure Sensor 5-Volt Reference 18 BN 4 Accessory Voltage 19 PK/BK 1039 Run/Crank Ignition 1 Voltage 20 RD/WH 840 Battery Positive Voltage 21 - - Not Used 22 WH 1310 EVAP Canister Vent Solenoid Control 23 - - Not Used 24 D-GN 890 Fuel Tank Pressure Sensor Signal 25 - - Not Used 26 OG/BK 380 A/C Refrigerant Pressure Sensor Signal 27 D-BU 1161 Accelerator Pedal Position Signal (1) 28 - - Not Used 29 TN 2759 Fuel Tank Pressure Sensor Low Reference 30 WH/BK 1164 Accelerator Pedal Position 5-Volt Reference (1) 31 - - Not Used 32 L-BU 20 Stop Lamp Supply Voltage 33 - - Not Used 34 PK 2014 Coolant Pump Relay Coil Control 35-36 - - Not Used 37 D-GN/WH 465 Fuel Pump Primary Relay Control 38 BN 5069 Engine Main Relay Coil Control 39 - - Not Used 40 BN/WH 419 Check Engine Indicator Control 41 L-BU 1162 Accelerator Pedal Position Signal (2) 42 - - Not Used 43 TN 1274 Accelerator Pedal Position 5-Volt Reference (2) 44-45 - - Not Used 46 PU 420 Torque Converter Clutch Brake Switch Signal 47 GY 2709 Fuel Tank Pressure Sensor 5-Volt Reference 48 YE 447 Starter Relay Coil Control 49-50 - - Not Used 51 D-GN 335 Low Speed Cooling Fan Relay Control 52 - - Not Used 53 BN/WH 379 Cruise Control Clutch Pedal Position Switch Signal 54 D-GN 1433 Clutch Start Switch Signal 55 - - Not Used 56 BK/WH 2751 Signal Ground

Powertrain Control Module (PCM) C2 Connector Part Information OEM: 15452126 Service: See Catalog 73-Way F GT 280 Micro 64 Sealed Pin Wire Color Circuit No. Function 1 RD 225 Generator Turn On Signal 2 D-GN 485 Throttle Position Sensor Signal (1) 3 - - Not Used 4 GY 596 5-Volt Reference 5 GY 2704 Manifold Absolute Pressure Sensor 5-Volt Reference 6 GY 2701 Throttle Position Sensor 5-Volt Reference 7 PU 486 Throttle Position Sensor Signal (2) 8 D-GN 6291 Manifold Absolute Pressure Sensor #2-Volt Reference 9 L-BU/BK 1688 5-Volt Reference 10-15 - - Not Used 16 PU 6413 EST Return Low Reference 17 YE 573 Crankshaft Position Sensor Signal (1) 18 PU 574 Crankshaft Position Sensor Low Reference (1) 19 - - Not Used 20 D-GN/WH 6292 Manifold Absolute Pressure #2 Low Reference 21 PK/BK 632 Camshaft Position Sensor Low Reference 22-24 - - Not Used 25 TN/WH 1669 Heated Oxygen Sensor Low Signal Bank 1 Sensor (2) 26 BN/WH 633 Camshaft Position Sensor Signal 27-28 - - Not Used 29 GY 1724 Supercharger Boost Solenoid Control 30 OG/BK 469 Manifold Absolute Pressure Sensor Low Reference 31 - - Not Used 32 TN 1667 Heated Oxygen Sensor Low Signal Bank 2 Sensor (1) 33 BK 1744 Fuel Injector Control (1) 34 - - Not Used 35 YE 410 Engine Coolant Temperature Sensor Signal 36 BK/WH 1704 Sensor Low Reference 37 GY 6337 Manifold Absolute Pressure Sensor #2 Signal 38 L-GN 432 Manifold Absolute Pressure Sensor Signal 39 BK 2752 Throttle Position Sensor Low Reference 40 BN/WH 6405 EST A Control 41 YE 492 Mass Air Flow Sensor Signal 42 D-GN/WH 6407 EST C Control 43 BK/WH 1423 Heated Oxygen Sensor Heater Low Control Bank 1 Sensor (2) 44 - - Not Used 45 GY 23 Generator Field Duty Cycle Signal 46 PU/WH 1668 Heated Oxygen Sensor High Signal Bank 1 Sensor (2) 47 - - Not Used 48 PU 1666 Heated Oxygen Sensor High Signal Bank 2 Sensor (1) 49-50 - - Not Used 51 TN 472 Intake Air Temperature Sensor Signal 52 BK 2761 Coolant Temperature Sensor Low Reference 53 L-GN/BK 1745 Fuel Injector Control (2) 54 L-BU/BK 844 Fuel Injector Control (4) 55 PK/BK 1746 Fuel Injector Control (3) 56-57 - - Not Used 58 D-GN 676 Heated Oxygen Sensor Heater High Control Bank 1 Sensor (1) 59 D-BU/WH 6406 EST B Control 60 L-BU/WH 6408 EST D Control 61-63 - - Not Used 64 BK 2760 Intake Air Temperature Sensor Low Reference 65 BN 582 Throttle Actuator Control Close 66 YE 581 Throttle Actuator Control Open 67 - - Not Used 68 D-BU 496 Knock Sensor Signal (1) 69 GY 1716 Knock Sensor Low Reference (1) 70-72 - - Not Used 73 BK/WH 451 Signal Ground

Powertrain Control Module (PCM) C3 (M86) Connector Part Information OEM: 15437820 Service: See Catalog 56-Way F Micro 64 Sealed (GY) Pin Wire Color Circuit No. Function 1-9 - - Not Used 10 TN 891 Boost Gauge Signal 11-14 - - Not Used 15 TN/BK 231 Oil Pressure Switch Signal 16-21 - - Not Used 22 WH/BK 2932 5-Volt Reference 23-30 - - Not Used 31 GY/BK 433 BARO Sensor Signal 32-35 - - Not Used 36 OG/BK 6014 Low Reference 37 D-GN/WH 428 EVAP Canister Purge Solenoid Control 38-43 - - Not Used 44 PU 401 VSS Low Signal 45 YE 400 VSS High Signal 46-56 - - Not Used

Engine Controls Connector End Views

Accelerator Pedal Position (APP) Sensor Connector Part Information OEM: 15326833 Service: See Catalog 6-Way M GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A TN 1274 Accelerator Pedal Position 5-Volt Reference (2) B L-BU 1162 Accelerator Pedal Position Signal (2) C PU 1272 Accelerator Pedal Position Low Reference (2) D BN 1271 Accelerator Pedal Position Low Reference (1) E D-BU 1161 Accelerator Pedal Position Signal (1) F WH/BK 1164 Accelerator Pedal Position 5-Volt Reference (1)

After Cooling Pump Connector Part Information OEM: 12131678 Service: See Catalog 2-Way F Mini Timer Sealed (BK) Pin Wire Color Circuit No. Function 1 BK 2022 Coolant Pump Control 2 BK/WH 451 Signal Ground

Barometric Pressure Sensor Connector Part Information OEM: 12129946 Service: See Catalog 3-Way F Metri-Pack 150 Series Sealed (GY) Pin Wire Color Circuit No. Function A OG/BK 6014 Barometric Pressure Sensor Low Reference B GY/BK 433 Barometric Pressure Sensor Signal C WH/BK 2932 Barometric Pressure Sensor 5-Volt Reference

Camshaft Position (CMP) Sensor Connector Part Information OEM: 15336029 Service: See Catalog 3-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function 1 GY 596 5-Volt Reference 2 BN/WH 633 Camshaft Position Sensor Signal 3 PK/BK 632 Camshaft Position Sensor Low Reference

Coolant Level Switch Connector Part Information OEM: 12052641 Service: See Catalog 2-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A L-GN 1478 Coolant Level Switch Signal B BK 650 Ground

Crankshaft Position (CKP) Sensor Connector Part Information OEM: 15363766 Service: See Catalog 2-Way F Timer JR-Timer Sealed (BK) Pin Wire Color Circuit No. Function A PU 574 Crankshaft Position Sensor Low Reference (1) B YE 573 Crankshaft Position Sensor Signal (1)

Engine Coolant Temperature (ETC) Sensor Connector Part Information OEM: 15363766 Service: See Catalog 2-Way F Timer JR-Power Sealed (BK) Pin Wire Color Circuit No. Function 1 BK 2761 Coolant Temperature Sensor Low Reference 2 YE 410 Engine Coolant Temperature Sensor Signal

Evaporative Emission (EVAP) Canister Purge Solenoid Valve Connector Part Information OEM: 12052643 Service: See Catalog 2-Way F Metri-Pack 150 Series Sealed (RD) Pin Wire Color Circuit No. Function A PK/WH 5291 Engine Main Relay Fused Control (2) B D-GN/WH 428 EVAP Canister Purge Solenoid Control

Evaporative Emissions (EVAP) Canister Vent Solenoid Valve Connector Part Information OEM: 12052643 Service: See Catalog 2-Way F Metri-Pack 150 Series Sealed (RD) Pin Wire Color Circuit No. Function A RD/WH 1840 Battery Positive Voltage B WH 1310 EVAP Canister Vent Solenoid Control

Fuel Injector 1 Connector Part Information OEM: 15326181 Service: See Catalog 2-Way F Micro-Pack 064 Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 5293 Ignition 1 Voltage B BK 1744 Fuel Injector 1 Control

Fuel Injector 2 Connector Part Information OEM: 15326181 Service: See Catalog 2-Way F Micro-Pack 064 Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 5293 Ignition 1 Voltage B L-BU/BK 844 Fuel Injector 2 Control

Fuel Injector 3 Connector Part Information OEM: 15326181 Service: See Catalog 2-Way F Micro-Pack 064 Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 5293 Ignition 1 Voltage B PK/BK 1746 Fuel Injector 3 Control

Fuel Injector 4 Connector Part Information OEM: 15326181 Service: See Catalog 2-Way F Micro-Pack 064 Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 5293 Ignition 1 Voltage B L-GN/BK 1745 Fuel Injector 4 Control

Fuel Pump Connector Part Information OEM: 776127-2 Service: See Catalog 2-Way F AMP (BK) Pin Wire Color Circuit No. Function 1 PK/BK 120 Fuel Pump Supply Voltage 2 BK 650 Ground

Fuel Tank Pressure (FTP) Sensor Connector Part Information 12059595 Service: See Catalog 3-Way Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A RD/PK 2759 Low Reference B GY/RD 890 Fuel Tank Pressure Sensor Signal C BN/WH 2709 5-Volt Reference

Heated Oxygen Sensor (HO2S) - 1 Connector Part Information OEM: 12176897 Service: See Catalog 4-Way F Metri-Pack 150 Series Sealed (L-GY) Pin Wire Color Circuit No. Function A TN 1667 Heated Oxygen Sensor Low Signal Bank 2 Sensor (1) B PU 1666 Heated Oxygen Sensor High Signal Bank 2 Sensor (1) C D-GN 676 Heated Oxygen Sensor Heater High Control Bank 1 Sensor (1) D PK/BK 5291 Engine Main Relay Fused Control (2)

Heated Oxygen Sensor (HO2S) - 2 Connector Part Information OEM: 12160825 Service: See Catalog 4-Way M Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A TN/WH 1669 Heated Oxygen Sensor Low Signal Bank 1 Sensor (2) B PU/WH 1668 Heated Oxygen Sensor High Signal Bank 1 Sensor (2) C BK/WH 1423 Heated Oxygen Sensor Heater Low Control Bank 1 Sensor (2) D PK/BK 5291 Engine Main Relay Fused Control (2)

Ignition Coil/Module 1 Connector Part Information OEM: 1928403440 Service: See Catalog 4-Way F Kompakt (BK) Pin Wire Color Circuit No. Function A PK/BK 5292 Ignition 1 Voltage B TN/WH 6405 IC 1 Control C VT 6413 Low Reference D BK 1350 Ground

Ignition Coil/Module 2 Connector Part Information OEM: 1928403440 Service: See Catalog 4-Way F Kompakt (BK) Pin Wire Color Circuit No. Function A PK/BK 5292 Ignition 1 Voltage B L-BU/WH 6408 IC 2 Control C VT 6413 Low Reference D BK 1350 Ground

Ignition Coil/Module 3 Connector Part Information OEM: 1928403440 Service: See Catalog 4-Way F Kompakt (BK) Pin Wire Color Circuit No. Function A PK/BK 5292 Ignition 1 Voltage B D-BU/WH 6406 IC 3 Control C VT 6413 Low Reference D BK 1350 Ground

Ignition Coil/Module 4 Connector Part Information OEM: 1928403440 Service: See Catalog 4-Way F Kompakt (BK) Pin Wire Color Circuit No. Function A PK/BK 5292 Ignition 1 Voltage B D-GN/WH 6407 IC 4 Control C VT 6413 Low Reference D BK 1350 Ground

Knock Sensor (KS) Connector Part Information OEM: 12077900 Service: See Catalog 2-Way F Metri-Pack 280 Series Sealed (BK) Pin Wire Color Circuit No. Function A D-BU 496 Knock Sensor Signal (1) B GY 1716 Knock Sensor Low Reference (1)

Manifold Absolute Pressure (MAP) Sensor Connector Part Information OEM: 12129946 Service: See Catalog 3-Way F Metri-Pack 150 Series Sealed (GY) Pin Wire Color Circuit No. Function A OG/BK 469 Manifold Absolute Pressure Sensor Low Reference B L-GN 432 Manifold Absolute Pressure Sensor Signal C GY 2704 Manifold Absolute Pressure Sensor 5-Volt Reference

Mass Air Flow (MAF) / Inlet Air Temperature (IAT) Sensor Connector Part Information OEM: 15326822 Service: See Catalog 5-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A YE 492 Mass Air Flow Sensor Signal B BK/WH 451 Signal Ground C PK/BK 5291 Engine Main Relay Fused Control (2) D BK 2760 Intake Air Temperature Sensor Low Reference E TN 472 Intake Air Temperature Sensor Signal

Supercharger Boost Gage Connector Part Information OEM: 12089248 Service: See Catalog 4-Way F Metri-Pack 150 Series (NA) Pin Wire Color Circuit No. Function A PK 439 Run/Crank Ignition 1 Voltage B GY 8 Instrument Panel Lamp Supply Voltage (1) C TN 891 Boost Gauge Signal D BK/WH 651 Signal Ground

Supercharger By - Pass Valve Solenoid Connector Part Information OEM: 12052641 Service: See Catalog 2-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK 1039 Run/Crank Ignition 1 Voltage B GY 1724 Supercharger Boost Solenoid Control

Supercharge Inlet Pressure Sensor Connector Part Information OEM: 10763258 Service: See Catalog 4-Way F Receptacle 2.8 Sealed (BK) Pin Wire Color Circuit No. Function 1 D-GN/WH 6292 Manifold Absolute Pressure #2 Low Reference 2 L-BU 6118 Manifold Air Temperature Sensor Signal 3 D-GN 6291 Manifold Absolute Pressure Sensor #2 Volt Reference 4 GY 6337 Manifold Absolute Pressure Sensor #2 Signal

Throttle Actuator Control (TAC) Module Connector Part Information OEM: 15326836 Service: See Catalog 8-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A D-GN 485 Throttle Position Sensor Signal (1) B L-BU/BK 1688 5-Volt Reference C BK 2752 Throttle Position Sensor Low Reference D PU 486 Throttle Position Sensor Signal (2) E YE 581 Throttle Actuator Control Open F BN 582 Throttle Actuator Control Close G GY 2701 Throttle Position Sensor 5-Volt Reference H BK/WH 1704 Sensor Low Reference

Removal Procedure

Note. In order to prevent internal damage to the PCM, the ignition must be OFF when disconnecting or reconnecting the PCM connector.

Note. Do not touch the connector pins or soldered components on the circuit board in order to prevent possible electrostatic discharge (ESD) damage to the PCM.

1. Using a scan tool, retrieve the percentage of remaining engine oil. Record the remaining engine oil life.
2. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
3. Disconnect the 3 powertrain control module (PCM) harness connectors from the PCM, noting proper orientation.
4. Use the retaining tab to release the PCM from the underhood junction block bracket.

Installation Procedure

1. Use the retaining tab to secure the PCM, when installing the PCM to the underhood junction block bracket.
2. Connect the PCM harness connectors to the PCM.
3. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
4. Program the PCM. Refer to «Control Module References»(/chevrolet/cobalt/i-2004-2010/remont/communication-devices/#computerintegrating-systems__control-module-references) in Computer/Integrating Systems.

CKP System Variation Learn Procedure

1. Install a scan tool.
2. Monitor the powertrain control module (PCM) for DTCs with a scan tool. If other DTCs are set, except DTC P0315, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/cobalt/i-2004-2010/remont/oem-general-information/#vehicle-dtc-information__diagnostic-trouble-code-dtc-list) in Vehicle DTC Information for the applicable DTC that set.
3. Using a scan tool, select the crankshaft position (CKP) variation learn procedure.
4. The scan tool instructs you to perform the following procedures: Accelerate to wide open throttle (WOT). Release the throttle when the fuel cutoff occurs. Observe the fuel cutoff specifications for the applicable engine. Engine should not accelerate beyond the calibrated RPM value. Release the throttle immediately if the value is exceeded. Block the drive wheels. Set the parking brake. DO NOT apply the brake pedal. Cycle the ignition from OFF to ON. Apply and hold the brake pedal. Start and idle the engine. Turn the A/C OFF. Vehicle must remain in Park or Neutral. The scan tool monitors certain component signals to determine if all the conditions are met to continue with the procedure. The scan tool only displays the condition that inhibits the procedure. The scan tool monitors the following components: The CKP sensor activity-If a CKP sensor condition exists, refer to the applicable DTC that set. The camshaft position (CMP) signal activity-If a CMP signal condition exists, refer to the applicable DTC that set. The engine coolant temperature (ECT)-If the engine coolant temperature is not warm enough, idle the engine until the engine coolant temperature reaches the correct temperature.
5. Using the scan tool, enable the CKP system variation learn procedure. Perform the following procedure: Accelerate to wide open throttle (WOT). Release when the fuel cutoff occurs. Test in progress.
6. The scan tool displays Learn Status: Learned This Ignition. If the scan tool indicates that DTC P0315 ran and passed, the CKP variation learn procedure is complete. If the scan tool indicates DTC P0315 failed or did not run, refer to «DTC P0315»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-dtc-p0132-to-p0340) . If any other DTCs set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/cobalt/i-2004-2010/remont/oem-general-information/#vehicle-dtc-information__diagnostic-trouble-code-dtc-list) in Vehicle DTC Information for the applicable DTC that set.
7. Turn OFF the ignition for 30 seconds after the learn procedure is completed successfully.
8. The CKP system variation learn procedure is also required when the following service procedures have been performed, regardless of whether DTC P0315 is set: An engine replacement A PCM replacement A crankshaft damper replacement A crankshaft replacement A CKP sensor replacement Any engine repairs which disturb the crankshaft to CKP sensor relationship

Note. Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

1. Turn OFF the ignition.
2. Drain the coolant system to below the engine coolant temperature (ECT) sensor. Refer to «Draining and Filling Cooling System (2.0L (LSJ))»(/chevrolet/cobalt/i-2004-2010/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (2.2L (L61))»(/chevrolet/cobalt/i-2004-2010/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
3. Disconnect the engine coolant temperature ECT sensor electrical connector.
4. Carefully remove the ECT sensor (1).

Note. Replacement components must be the correct part number for the application. Components requiring the use of the thread locking compound, lubricants, corrosion inhibitors, or sealants are identified in the service procedure. Some replacement components may come with these coatings already applied. Do not use these coatings on components unless specified. These coatings can affect the final torque, which may affect the operation of the component. Use the correct torque specification when installing components in order to avoid damage.

Note. Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

1. If you are reinstalling the original sensor, or if you are installing a new sensor without a sealer, coat the threads with sealer Saturn P/N 21485278 or an equivalent.
2. Install the ECT sensor (1). Tighten: Tighten the ECT sensor to 22 N.m (16 lb ft).
3. Connect the ECT sensor electrical connector.
4. Refill the engine coolant system. Refer to «Draining and Filling Cooling System (2.0L (LSJ))»(/chevrolet/cobalt/i-2004-2010/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (2.2L (L61))»(/chevrolet/cobalt/i-2004-2010/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.

1. Disconnect the intake air temperature (IAT) sensor harness connector.
2. Remove the IAT sensor bolt.
3. While twisting the IAT sensor (3), pull the sensor from the engine.

1. Press the IAT sensor (3) into the engine.
2. Install the IAT sensor bolt. Tighten: Tighten the bolt to 10 N.m (89 lb in).
3. Connect the IAT sensor harness connector.

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/cobalt/i-2004-2010/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the left front tire and wheel. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/cobalt/i-2004-2010/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
3. Remove the left front fender liner. Refer to «Front Fender Liner Replacement»(/chevrolet/cobalt/i-2004-2010/remont/exterior-body-panels/#body-front-end) in Body Front End.
4. Remove the left front splash shield-engine. Refer to «Splash Shield Replacement - Engine»(/chevrolet/cobalt/i-2004-2010/remont/exterior-body-panels/#body-front-end__splash-shield-replacement-engine) in Body Front End.
5. Disconnect the electrical connector from the mass air flow (MAF) sensor.
6. Remove the 2 fasteners.
7. Remove the MAF sensor from the air cleaner housing.

1. Install the MAF sensor into the air cleaner housing.
2. Secure the MAF sensor to the air cleaner housing with the 2 fasteners. Tighten: Tighten the 2 fasteners to 2 N.m (18 lb in).
3. Connect the MAF sensor electrical connector.
4. Install the left front splash shield-engine. Refer to «Splash Shield Replacement - Engine»(/chevrolet/cobalt/i-2004-2010/remont/exterior-body-panels/#body-front-end__splash-shield-replacement-engine) in Body Front End.
5. Install the left front fender liner. Refer to «Front Fender Liner Replacement»(/chevrolet/cobalt/i-2004-2010/remont/exterior-body-panels/#body-front-end) in Body Front End.
6. Install the left front tire and wheel. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/cobalt/i-2004-2010/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
7. Lower the vehicle.

1. Disconnect the temperature manifold absolute pressure (TMAP) sensor harness connector.
2. Remove the TMAP sensor from the intake manifold.
3. Inspect the seal for damage.

1. Install the TMAP sensor into the intake manifold. Tighten: Tighten the bolt to 10 N.m (89 lb in).
2. Connect the TMAP sensor harness connector.

1. Disconnect the supercharger inlet pressure (SCIP) sensor harness connector.
2. Remove the SCIP sensor (1) from the supercharger.
3. Inspect the seal for damage.

1. Install the SCIP sensor (1) into the intake manifold. Tighten: Tighten the bolt to 10 N.m (89 lb in).
2. Connect the SCIP sensor harness connector.

Tools Required

J 39194-C Oxygen Sensor Wrench. See Special Tools .

Note. The oxygen sensor uses a permanently attached pigtail and connector. Do not remove the pigtail from the oxygen sensor. Damage to or removal of the pigtail connector could affect proper operation of the oxygen sensor.

Note. The use of excessive force may damage the threads in the exhaust manifold/pipe.

1. Remove the exhaust manifold heat shield. Refer to «Exhaust Manifold Replacement (L61)»(/chevrolet/cobalt/i-2004-2010/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
2. Disconnect the oxygen sensor harness connector.
3. Remove the oxygen sensor using J 39194-C . See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .

1. Coat the threads of the oxygen sensor with anti-seize compound Saturn P/N 21485279, if necessary.
2. Install the oxygen sensor. Tighten: Tighten the oxygen sensor to 30 N.m (22 lb ft).
3. Connect the oxygen sensor harness connector.
4. Install the exhaust manifold heat shield. Refer to «Exhaust Manifold Replacement (L61)»(/chevrolet/cobalt/i-2004-2010/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.

J 39194-C Oxygen Sensor Wrench. See Special Tools .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/cobalt/i-2004-2010/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the wheel drive shaft heat shield. Refer to «Wheel Drive Shaft Heat Shield Replacement»(/chevrolet/cobalt/i-2004-2010/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
3. Note the routing of the heated oxygen sensor (HO2S) electrical harness.
4. Disconnect the HO2S electrical connector (2), in the engine compartment.
5. Carefully bend the edge of the channel on the LH side of the exhaust heat shield outboard, just enough to release the HO2S electrical harness (1).
6. Using the J 39194 carefully remove the HO2S.
7. Lower the HO2S electrical harness away from the underbody.

1. If reinstalling the old HO2S, coat the threads with anti-seize compound, Saturn P/N 24185279, or equivalent.
2. Carefully install the HO2S to the pipe.
3. Using the J 39194 , or equivalent, tighten the HO2S. Tighten: Tighten the HO2S to 41 N.m (30 lb ft).
4. Install the HO2S electrical harness into position as noted before removal.
5. Carefully bend the edge of the channel (1) on the LH side of the exhaust heat shield inboard, just enough to secure the HO2S electrical harness in the channel.
6. Connect the HO2S electrical connector (2).
7. Install the wheel drive shaft heat shield. Refer to «Wheel Drive Shaft Heat Shield Replacement»(/chevrolet/cobalt/i-2004-2010/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
8. Lower the vehicle.

1. Disconnect the connector position assurance (CPA) from the accelerator pedal position (APP) sensor connector.
2. Disconnect the APP sensor harness connector.
3. Remove the APP assembly attachment bolts from the brake pedal assembly.
4. Remove the APP assembly from the vehicle.

1. Install the upper attachment bolt into the APP assembly.
2. Install the APP assembly into the vehicle.
3. Install the attachment bolts into the APP assembly. Tighten: Tighten the accelerator pedal position assembly-to-brake bracket bolt to 9 N.m (80 lb in).
4. Connect the APP sensor harness connector. Push the connector in until the lock position is felt, then pull back to confirm engagement.
5. Install the APP sensor connect CPA.

Note. Do not use solvent of any type when cleaning the gasket surfaces on the intake manifold and the throttle body assembly, as damage to the gasket surfaces and throttle body assembly may result. Use care in cleaning the gasket surfaces on the intake manifold and the throttle body assembly, as sharp tools may damage the gasket surfaces.

Note. Do not use any solvent that contains Methyl Ethyl Ketone (MEK). This solvent may damage fuel system components.

1. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
2. Disconnect the evaporative emission (EVAP) purge line.
3. Disconnect the throttle body control harness connector.
4. Remove the throttle body attaching bolts.
5. Remove the throttle body and gasket from the supercharger.

1. Inspect the throttle body gasket and replace if necessary.
2. Install the throttle body to the supercharger.
3. Install the throttle body attaching bolts. Tighten: Tighten the throttle body attaching bolts to 10 N.m (89 lb in).
4. Connect the throttle body control harness connector.
5. Connect the EVAP purge line.
6. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .

J 34730-1A Fuel Pressure Gage. See Special Tools .

1. Turn the ignition OFF.
2. Disconnect the battery negative cable in order to avoid possible fuel discharge if an accidental attempt is made to start the engine. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
3. Loosen the fuel filler cap to relieve the fuel tank vapor pressure.
4. Remove the cap from the fuel pressure service port.
5. Remove the engine identification cover nuts and cover.
6. Connect the J 34730-1A to the fuel pressure service port connection. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) . Wrap a shop towel around the port while connecting the gage in order to avoid spillage. Refer to «Fuel Pressure Gage Installation and Removal»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
7. Install the bleed hose of the J 34730-1A into an approved fuel container. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .
8. Open the bleed valve on the J 34730-1A in order to bleed the fuel system pressure. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) . The fuel connections are now safe for servicing.
9. Place a shop towel under the fuel pressure service port to catch any remaining fuel spillage.
10. Disconnect the J 34730-1A from the fuel pressure service port connection. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) . Refer to «Fuel Pressure Gage Installation and Removal»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
11. Drain any fuel remaining in the gage into an approved fuel container.
12. Install the cap to the fuel pressure service port.

J 34730-1A Fuel Pressure Gage. See Special Tools .

Note. Clean all of the following areas before performing any disconnections in order to avoid possible contamination in the system: The fuel pipe connections The hose connections The areas surrounding the connections

1. Remove the cap from the fuel pressure service port connection.
2. Connect the J 34730-1A to the fuel pressure service connection. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) . Wrap a shop towel around the fitting while connecting the gage to avoid spillage.
3. Turn the ignition ON, with the engine OFF.
4. Place the bleed hose of the J 34730-1A into an approved fuel container. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .
5. Open the bleed valve on the J 34730-1A in order to bleed the air from the fuel pressure gage. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .
6. Command the fuel pump ON with a scan tool.
7. Close the bleed valve on the J 34730-1A . See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .
8. Inspect for fuel leaks.

1. Ensure the fuel pump is OFF.
2. Place the bleed hose of the J 34730-1A into an approved fuel container. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .
3. Open the bleed valve on the J 34730-1A in order to bleed the fuel system pressure. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .
4. Place a shop towel under the fuel pressure service connection to catch any remaining fuel spillage.
5. Remove the J 34730-1A from the fuel pressure service connection. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .
6. Drain any fuel remaining in the J 34730-1A into an approved fuel container. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .
7. Inspect for leaks using the following procedure: Turn the ignition ON, with the engine OFF for 2 seconds. Turn the ignition OFF for 10 seconds. Turn the ignition ON, with the engine OFF for 2 seconds. Turn the ignition OFF. Inspect for leaks.
8. Install the cap on the fuel pressure service connection.

J 37088-A Fuel Line Disconnect Tool Set. See Special Tools .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
2. Remove the retainer from the quick-connect fitting, if applicable.
3. Blow dirt out of the fitting using compressed air.
4. Choose the correct tool from J 37088-A tool set for the size of the fitting. Insert the tool into the female connector, then push inward to release the locking tabs.
5. Pull the connection apart.
6. Using a clean shop towel, wipe off the male pipe end.
7. Inspect both ends of the fitting for dirt and burrs. Clean or replace the components as required.

1. Apply a few drops of clean engine oil to the male pipe end.
2. Push both sides of the fitting together to cause the retaining tabs to snap into place.
3. Once installed, pull on both sides of the fitting to make sure the connection is secure.
4. Install the retainer to the quick-connect fitting, if applicable.

1. J 43290 Fuel Tank Siphoning Hose
2. J 42960-2 Fuel Flapper Door Holder. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .

Draining Procedures

1. Remove the fuel filler cap.
2. Install the J 42960-2 , or equivalent, into the fuel fill pipe in order to hold the door open. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .
3. Insert the J 43290 (2) through the J 42960-2 (1) and into the filler pipe. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .
4. Continue to insert the J 43290 (2) into the filler pipe until the hose exits the valve (1) and reaches the bottom of the tank.
5. Use an air operated pump device in order to drain as much fuel through the J 43290 (1) as possible.

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
2. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/cobalt/i-2004-2010/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Disconnect the fuel feed and return lines from the fuel filter.
5. Cap or plug the fuel tank feed and return pipes to prevent fuel loss and/or contamination.
6. Disconnect the following evaporative emission (EVAP) pipe fittings, for access to disconnect the fuel filler hose from the tank. The EVAP purge pipe (2) from the EVAP canister The fuel tank EVAP vapor pipe (3) from the EVAP canister
7. Cap or plug the EVAP purge (2) and vapor (3) pipes to prevent contamination.
8. Loosen the fuel filler hose clamp (1) at the fuel tank.
9. Disconnect the fuel filler hose from the fuel tank.
10. Disconnect the fuel pump module harness electrical connector from the vehicle underbody connector.
11. Release the exhaust extension pipe insulators from the underbody hangers.
12. Release the muffler insulator from the underbody hanger and slowly lower the exhaust to rest on the rear axle beam.
13. Have an assistant support the fuel tank during fuel tank strap removal, and during tank removal.
14. Remove the LH fuel tank strap bolts and the strap.
15. Remove the RH tank strap bolts and the strap.
16. In order to clear the exhaust extension pipe, slowly lower the RH side of the fuel tank. Use care in feeding the fuel feed and return pipes, the EVAP vapor pipe, and the fuel pump module electrical harness to clear the axle.
17. Once the tank is clear of the RH frame rail, remove the fuel tank down and toward the RH side of the vehicle.
18. If the fuel tank only is to be replaced, remove the fuel pump module assembly from the fuel tank. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .

1. If fuel tank replacement was necessary, install the fuel pump module assembly to the fuel tank. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
2. Have an assistant support the fuel tank during fuel tank and fuel tank strap installation.
3. Begin to install the LH side of the fuel tank over the exhaust pipe.
4. Raise the RH side of the fuel tank into position inboard of the RH frame rail. Use care in feeding the fuel feed and return pipes, the EVAP vapor pipe, and the fuel pump module electrical harness over the rear axle.
5. Install the RH fuel tank strap and strap bolts.
6. Install the LH fuel tank strap and strap bolts.
7. Tighten the fuel tank strap bolts. Tighten: Tighten the bolts to 25 N.m (18 lb ft).
8. Raise the exhaust into position and install the muffler insulators to the underbody hanger.
9. Install the exhaust extension pipe insulators to the underbody hangers.
10. Connect the fuel pump module harness electrical connector to the vehicle underbody connector.
11. Connect the fuel filler hose to the fuel tank.
12. Tighten the fuel filler hose clamp (1) at the fuel tank. Tighten: Tighten the clamp to 4.5 N.m (40 lb in).
13. Remove the caps or plugs from the EVAP purge and vapor pipes.
14. Connect the EVAP purge pipe (2) and vapor pipe (3) to the EVAP canister.
15. Remove the caps or plugs from the fuel tank feed and return pipes.
16. Connect the fuel feed and return lines to the fuel filter.
17. Lower the vehicle.
18. Refill the fuel tank.
19. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
20. Inspect for fuel leaks using the following procedure: Turn ON the ignition, with the engine OFF for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition, with the engine OFF. Inspect for fuel leaks.

1. Remove the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
2. Disconnect the fuel pump module harness electrical connector from the fuel tank pressure sensor.
3. Position 2 flat-bladed screwdrivers, one on each side of the sensor, near the vacuum port.
4. Carefully use the screwdrivers to lift and release the sensor from the fuel pump module.

1. Install the fuel tank pressure sensor to the fuel pump module assembly. Ensure that the sensor grommet is fully seated to the pump module.
2. Connect the pump module electrical connector to the fuel tank pressure sensor.
3. Install the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .

1. Remove the fuel fill cap.
2. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
3. Remove the fuel filler pocket. Refer to «Fuel Filler Pocket Replacement»(/chevrolet/cobalt/i-2004-2010/remont/exterior-body-panels/#body-rear-end) in Body Rear End.
4. Remove the fuel filler pipe assembly upper retaining bolt.
5. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/cobalt/i-2004-2010/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
6. Disconnect the evaporative emission (EVAP) vent pipe (1) from the EVAP canister. Refer to CELL LINK 16239.
7. Loosen the fuel filler hose clamp (1) at the fuel tank.
8. Remove the fuel filler pipe assembly lower retaining bolt.
9. Disconnect the fuel filler hose from the fuel tank.
10. Remove the fuel filler pipe assembly.

1. Install the fuel filler pipe assembly into position on the vehicle.
2. Connect the fuel filler hose to the fuel tank.
3. Install the fuel filler pipe assembly lower retaining bolt. Tighten: Tighten the bolt to 10 N.m (89 lb in).
4. Tighten the fuel filler hose clamp (1) at the fuel tank. Tighten: Tighten the clamp to 4.5 N.m (40 lb in).
5. Connect the EVAP vent pipe (1) to the EVAP canister. Refer to CELL LINK 16239.
6. Lower the vehicle.
7. Install the fuel filler pipe assembly upper retaining bolt. Tighten: Tighten the bolt to 10 N.m (89 lb in).
8. Install the fuel filler pocket. Refer to «Fuel Filler Pocket Replacement»(/chevrolet/cobalt/i-2004-2010/remont/exterior-body-panels/#body-rear-end) in Body Rear End.
9. Refill the fuel tank.
10. Install the fuel fill cap.

1. Remove the fuel pump module assembly. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-22l-introduction) .
2. Release the fuel level sensor wiring harness from the molded-in tab (1) on the pump module bowl.
3. Disconnect the fuel level sensor electrical connector from the pump module.
4. Depress the retaining tab (2) on the sensor and begin to slide the level sensor away from the pump module.
5. Carefully slide the level sensor the rest of the way off of the pump module.

1. Carefully slide the fuel level sensor into the slots on the fuel pump module bowl.
2. Secure the retaining tab (2) on the sensor into the slot on the pump module bowl.
3. Connect the fuel level sensor electrical connector to the pump module.
4. Install the fuel level sensor wiring harness to the molded-in tab (1) on the pump module bowl.
5. Install the fuel pump module assembly. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-22l-introduction) .

1. SA9156E Fuel Tank Lock Ring Remover
2. J 39765 Fuel Sender Lock Nut Wrench. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .

1. Remove the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
2. Release the retaining tab on the fuel tank retainer used to secure the fuel pump module pipes in position on the tank.
3. Release the fuel pump module electrical harness from the retaining slot on the tank.
4. Disconnect the fuel pump module harness electrical connector from the fuel tank pressure sensor.
5. Using the SA9156E , or J 39765 (1), carefully rotate to release the fuel pump module retaining lock ring. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .
6. Remove the fuel pump module retaining lock ring, by sliding the ring over the module pipes and electrical harness.
7. Slowly raise the fuel pump module assembly until the fuel level sensor float arm is just visible. Ensure that the fuel level sensor harness connector clears the tank opening.
8. Tilt the pump module toward the rear of the fuel tank to enable the level sensor float arm to clear the tank opening. Remove the pump module from the tank.
9. Carefully discard the fuel in the pump module reservoir bowl into an approved fuel container.
10. Remove and discard the fuel pump module-to-fuel tank seal (1).

1. Install a NEW fuel pump module-to-fuel tank seal (1).
2. Tilt the pump module toward the rear of the fuel tank to enable the level sensor float arm to clear the tank opening. Install the fuel pump module to the fuel tank.
3. Slowly lower the fuel pump module assembly into the tank. Ensure that the fuel level sensor harness connector is positioned properly.
4. Install the fuel pump module retaining lock ring over the module pipes and electrical harness, and into position on the top of the module.
5. Using the SA9156E , or J 39765 (1), carefully rotate to fully secure the fuel pump module retaining lock ring. See «Special Tools»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__special-tools) .
6. Connect the fuel pump module harness electrical connector to the fuel tank pressure sensor.
7. Secure the fuel pump module electrical harness into the retaining slot on the tank.
8. Secure the retaining tab on the fuel tank retainer used to secure the fuel pump module pipes in position on the tank.
9. Install the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .

1. Remove the engine cover.
2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
3. Disconnect the engine fuel feed pipe from the chassis fuel flex hose. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
4. Use a back up wrench on the fuel rail and disconnect the fuel feed pipe.
5. Remove the fuel feed pipe fastener located on the engine.
6. Remove the engine fuel feed pipe.

1. Install the fuel feed pipe to the fuel rail. Tighten: Using a backup wrench on the fuel rail tighten the fuel feed pipe to 14 N.m (10 lb ft).
2. Install the engine fuel feed pipe fastener located on the engine. Tighten: Tighten the fuel feed pipe fastener to 10 N.m (89 lb in).
3. Connect the engine fuel feed pipe to the chassis fuel flex hose. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
4. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
5. Inspect for leaks using the following procedure: With the engine OFF, turn ON the ignition for 2 seconds. Inspect for fuel leaks. Turn the ignition OFF. With the engine OFF, turn ON the ignition for 2 seconds. Inspect for fuel leaks. Turn the ignition OFF.
6. Install the engine cover and nuts. Tighten: Tighten the nuts to 10 N.m (89 lb in).

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
2. Remove the pipe retaining clip (1) from the fuel feed pipe.
3. Disconnect the fuel feed pipe from the engine fuel rail. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
4. Cap or plug the fuel pipe and the engine fuel rail to prevent contamination.
5. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/cobalt/i-2004-2010/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
6. Remove the evaporative emission (EVAP) canister for pipe removal access. Refer to «Evaporative Emission (EVAP) Canister Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction)
7. Disconnect the fuel filter from the engine feed fuel pipe (1). Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
8. Remove the rear brake pipe bracket retaining nuts and release the brackets from the body studs.
9. Release the pipe retainers (1) from the vehicle underbody.
10. Remove the fuel feed pipe from the pipe retainers.
11. Lower the rear of the pipe while moving the pipe rearward slightly, then lower the front of the pipe.
12. Remove the fuel feed pipe from the vehicle.

1. Position the fuel feed pipe to the vehicle.
2. With the rear of the pipe positioned slightly rearward and down, raise the front of the pipe into position.
3. Install the remainder of the pipe into position.
4. Install the fuel feed pipe to the pipe retainers.
5. Secure the pipe retainers (1) to the vehicle underbody.
6. Install the rear brake hose brackets to the body studs and install the rear brake hose bracket retaining nuts. Tighten: Tighten the nuts to 10 N.m (89 lb in).
7. Connect the fuel filter to the engine feed fuel pipe (1). Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
8. Install the EVAP canister. Refer to «Evaporative Emission (EVAP) Canister Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction)
9. Lower the vehicle.
10. Remove the caps or plugs from the fuel pipe and the engine fuel rail.
11. Connect the fuel feed pipe to the engine fuel rail. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
12. Install the pipe retaining clip (1) to the fuel feed pipe.
13. Connect the negative battery cable.
14. Inspect for fuel leaks using the following procedure: Turn ON the ignition, with the engine OFF for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition, with the engine OFF. Inspect for fuel leaks.

Fuel System Cleaning

1. Remove the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
2. Remove the fuel pump module assembly. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
3. Inspect the fuel pump module strainer. Replace the pump module assembly if the fuel strainer is contaminated.
4. Flush the fuel tank with hot water.
5. Pour the water out of the fuel sender assembly opening in the fuel tank. Rock the fuel tank in order to be sure that the removal of the water from the fuel tank is complete.
6. Allow the tank to dry completely before reassembly.
7. Disconnect the fuel feed pipe at the engine fuel rail.
8. Clean the fuel pipes by applying air pressure in the opposite direction of the fuel flow.
9. Connect the fuel feed pipe to the engine fuel rail.
10. Install the fuel pump module assembly. Refer to «Fuel Sender Assembly Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
11. Install the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
12. Replace the fuel filter.

1. Remove the coolant overflow pipe.
2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
3. Use a back up wrench on the fuel rail and disconnect the fuel supply pipe.
4. Remove the fuel rail attaching studs.
5. Remove the fuel rail using the following procedure: Pull the fuel rail back and upward to remove the fuel injectors from the cylinder head ports. Rotate the fuel rail in order to position the injectors downward. Remove the fuel rail.
6. Disconnect the fuel injector harness connectors.
7. Remove the fuel injectors. Refer to «Fuel Injector Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .

1. Install the fuel injectors. Refer to «Fuel Injector Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
2. Connect the fuel injector harness connectors. Pull back to insure the connectors are locked in place.
3. Install the fuel rail using the following procedure: With the fuel injectors positioned downward, lower the fuel injectors into the cylinder head ports. Align the injectors by rotating the fuel rail forward. Carefully push the fuel injectors into the cylinder head ports.
4. Install the fuel rail attaching studs. Tighten: Tighten the fuel rail studs to 10 N.m (89 lb in).
5. Install the fuel supply pipe. Tighten: Using a backup wrench on the fuel rail tighten the fuel supply pipe to 14 N.m (10 lb ft).
6. Install the coolant overflow pipe. Tighten: Tighten the pipe bolt to 8 N.m (71 lb in).
7. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
8. Inspect for fuel leaks using the following procedure: Turn ON the ignition, with the engine OFF for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.

1. Remove the fuel rail. Refer to «Fuel Rail Assembly Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
2. Remove the fuel injector retainer clip (3).
3. Remove the fuel injectors (5) from the fuel rail.
4. Remove and discard the fuel injector O-rings (4, 7).

1. Install the O-rings on the fuel injector (4, 7).
2. Install the fuel injector clip (3) on the fuel injector (5).
3. Install the fuel injector in the fuel rail with the connector facing upward.
4. Install the fuel rail. Refer to «Fuel Rail Assembly Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .

1. Disconnect the evaporative emission (EVAP) canister purge valve harness connector.
2. Disconnect the vacuum pipe from the EVAP canister purge valve.
3. Disconnect the purge pipe from the EVAP canister purge valve.
4. Remove the EVAP canister purge valve and bracket.
5. Remove the EVAP canister purge valve from the purge bracket.
6. Inspect for carbon release in the EVAP canister purge valve ports. Refer to «Evaporative Emission (EVAP) System Cleaning»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .

1. Install the EVAP canister purge valve on to the purge bracket.
2. Install the EVAP canister purge valve and bracket. Tighten: Tighten the purge bracket nut to 8 N.m (71 lb in).
3. Connect the purge pipe to the EVAP canister purge valve.
4. Connect the vacuum pipe to the EVAP canister purge valve.
5. Connect the EVAP canister purge valve harness connector.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/cobalt/i-2004-2010/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Disconnect the electrical connector from the evaporative emission (EVAP) canister vent solenoid valve.
3. Clean away any debris that may be present around the EVAP canister vent valve.
4. Remove the EVAP canister retaining bolt (1).
5. Lower the EVAP canister.
6. Rotate the EVAP canister vent valve counterclockwise to release from the locked position.
7. Remove the vent valve from the EVAP canister.

1. Insert the EVAP canister vent solenoid valve into the EVAP canister, with the valve aligned to the released position.
2. Rotate vent valve clockwise to secure into the locked position.
3. Install the EVAP canister and retaining bolt (1). Tighten: Tighten the bolt to 10 N.m (89 lb in).
4. Connect the electrical connector to the EVAP canister vent valve.
5. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/cobalt/i-2004-2010/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Disconnect the electrical connector from the evaporative emission (EVAP) canister vent solenoid valve.
3. Disconnect the hose connections (1, 2, 3) from the EVAP canister.
4. Remove the EVAP canister retaining bolt (1).
5. Remove the EVAP canister assembly toward the outboard side of the vehicle.
6. If the EVAP canister is to be reused, inspect the canister for loose carbon.

1. Insert the retaining tab of the EVAP canister into the slotted bracket on the vehicle underbody.
2. Install the EVAP canister retaining bolt (1). Tighten: Tighten the bolt to 10 N.m (89 lb in).
3. Connect the hose connections (1, 2, 3) to the EVAP canister.
4. Connect the electrical connector to the EVAP canister vent solenoid valve.
5. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/cobalt/i-2004-2010/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Clean away any debris that may be present around the evaporative emission (EVAP) canister vent filter cover.
3. Carefully release the canister filter cover rear retaining tabs.
4. Carefully release the canister filter cover forward retaining tabs and remove the cover from the EVAP canister.
5. Remove the filter from the canister and discard the filter.
6. Remove the seal from the filter cover and discard the seal.
7. Clean the inside of the EVAP canister filter housing with a clean shop towel.

1. Install a NEW seal to the filter cover. Ensure that the seal is properly seated to the cover.
2. Install a NEW filter to the canister filter housing.
3. Install the filter cover to the EVAP canister.
4. Lower the vehicle.

J 41413 EVAP Pressure and Purge Station

Inspection Procedure

Note. Refer to CLEAN, DRY, LOW PRESSURE GAS SOURCE NOTICE Notice in Cautions and Notices.

1. Turn OFF the ignition.
2. Remove the EVAP canister purge valve. Refer to «Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
3. Lightly tap the EVAP canister purge valve on a hard surface.
4. Inspect for carbon particles exiting either of the vacuum ports. If no carbon particles were detected, but a blockage was detected during a diagnostic procedure, install the original EVAP canister purge valve. Continue with the cleaning procedure. If carbon particles are found during the inspection procedure, continue with the cleaning procedure. If a diagnostic procedure directed you to replace the EVAP canister purge valve and no carbon particles were detected, replace the EVAP canister purge valve. Return to the published service procedure.

Cleaning Procedure

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/cobalt/i-2004-2010/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the EVAP canister. Refer to «Evaporative Emission (EVAP) Canister Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
3. Turn OFF the main valve on the J 41413 .
4. Disconnect the hose from the diagnostic station pressure regulator.
5. Using a section of vacuum hose, connect one end onto the EVAP pressure/purge diagnostic station pressure regulator.
6. Connect the other end of the vacuum hose to the canister side of the purge pipe.
7. Turn ON the main nitrogen cylinder valve and continue to discharge nitrogen for 15 seconds.
8. If the nitrogen does not clear the blockage, replace the purge pipe.
9. Return the EVAP pressure/purge diagnostic station to the stations original condition.
10. Install a new EVAP canister. Refer to «Evaporative Emission (EVAP) Canister Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
11. Lower the vehicle.
12. Install a new EVAP canister purge valve. Refer to «Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
13. Return to the diagnostic table that sent you here.

1. Disconnect the ignition coil connectors from the ignition coils.
2. Remove the retaining bolts from the ignition coils.
3. Remove the ignition coils from the engine.

1. Install the ignition coil.
2. Install the ignition coil retaining bolts. Tighten: Tighten the ignition coil retaining bolts to 10 N.m (89 lb in).
3. Replace the ignition coil connectors.

Spark Plug Usage

1. Ensure that the correct spark plug is installed. An incorrect spark plug causes driveability conditions. Refer to «Ignition System Specifications»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__ignition-system-specifications) for the correct spark plug.
2. Ensure that the spark plug has the correct heat range. An incorrect heat range causes the following conditions: Spark plug fouling - colder plug Pre-ignition causing spark plug and/or engine damage - hotter plug

Spark Plug Inspection

1. Inspect the terminal post (1) for damage. Inspect for a bent or broken terminal post (1). Test for a loose terminal post (1) by twisting and pulling the post. The terminal post (1) should NOT move.
2. Inspect the insulator (2) for flashover or carbon tracking, soot. This is caused by the electrical charge traveling across the insulator (2) between the terminal post (1) and ground. Inspect for the following conditions: Inspect the spark plug boot for damage. Inspect the spark plug recess area of the cylinder head for moisture, such as oil, coolant, or water. A spark plug boot that is saturated causes arcing to ground.
3. Inspect the insulator (2) for cracks. All or part of the electrical charge may arc through the crack instead of the electrodes (3, 4).
4. Inspect for evidence of improper arcing. Measure the gap between the center electrode (4) and the side electrode (3) terminals. Refer to «Ignition System Specifications»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__ignition-system-specifications) . An excessively wide electrode gap can prevent correct spark plug operation. Inspect for the correct spark plug torque. Refer to «Ignition System Specifications»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__ignition-system-specifications) . Insufficient torque can prevent correct spark plug operation. An over torqued spark plug, causes the insulator (2) to crack. Inspect for signs of tracking that occurred near the insulator tip instead of the center electrode (4). Inspect for a broken or worn side electrode (3). Inspect for a broken, worn, or loose center electrode (4) by shaking the spark plug. A rattling sound indicates internal damage. A loose center electrode (4) reduces the spark intensity. Inspect for bridged electrodes (3, 4). Deposits on the electrodes (3, 4) reduce or eliminates the gap. Inspect for worn or missing platinum pads on the electrodes (3, 4) If equipped. Inspect for excessive fouling.
5. Inspect the spark plug recess area of the cylinder head for debris. Dirty or damaged threads can cause the spark plug not to seat correctly during installation.

Spark Plug Visual Inspection

1. Normal operation-Brown to grayish-tan with small amounts of white powdery deposits are normal combustion by-products from fuels with additives.
2. Carbon Fouled-Dry, fluffy black carbon, or soot caused by the following conditions: Rich fuel mixtures Leaking fuel injectors Excessive fuel pressure Restricted air filter element Incorrect combustion Reduced ignition system voltage output Weak coils Worn ignition wires Incorrect spark plug gap Excessive idling or slow speeds under light loads can keep spark plug temperatures so low that normal combustion deposits may not burn off.
3. Deposit Fouling-Oil, coolant, or additives that include substances such as silicone, very white coating, reduces the spark intensity. Most powdery deposits will not effect spark intensity unless they form into a glazing over the electrode.

Note. This engine has aluminum cylinder heads. Do not remove the spark plugs from a hot engine, allow it to cool first. Removing the spark plugs from a hot engine may cause spark plug thread damage or cylinder head damage.

1. Remove the ignition coils. Refer to «Ignition Coil(s) Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
2. Remove the spark plugs with a spark plug socket.
3. Inspect the spark plugs. Refer to «Spark Plug Inspection»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__spark-plug-inspection) .

1. Gap the spark plug, using round wire type spark plug gap gage. Gap: Adjust the spark plug gap to 1.14 mm (0.045 in).
2. Install the spark plugs with a spark plug socket. Tighten: Tighten the spark plugs to 20 N.m (15 lb ft).
3. Install the ignition coils. Refer to «Ignition Coil(s) Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .

1. Remove the starter. Refer to «Starter Motor Replacement (2.2L (L61))»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (2.0L (LSJ))»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Disconnect the crankshaft position (CKP) sensor electrical connector.
3. Remove the CKP sensor bolt.
4. Remove the CKP sensor (2).

1. Inspect the CKP sensor O-ring and lubricate with a mineral based grease.
2. Gently insert the CKP sensor (2) into the block.
3. Install the CKP sensor bolt. Tighten: Tighten the CKP sensor bolt to 10 N.m (89 lb in).
4. Reconnect the CKP sensor electrical connector.
5. Install the starter. Refer to «Starter Motor Replacement (2.2L (L61))»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (2.0L (LSJ))»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
6. Perform the CKP system Variation Learn Procedure. Refer to «CKP System Variation Learn Procedure»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction__ckp-system-variation-learn-procedure) .

1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Remove the underhood junction block. Refer to «Underhood Electrical Center or Junction Block Bracket Replacement»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management) in Wiring Systems.
3. Disconnect the electrical connector from the camshaft position (CMP) sensor.
4. Remove the CMP sensor studs.
5. Remove the CMP sensor.

1. Rotate the crankshaft until number 4 piston is at top dead center (TDC) on the compression stroke. Refer to the crankshaft damper-to-front-cover timing marks.
2. Install the NEW camshaft position sensor housing seal.
3. Align the timing mark on the housing with the timing mark on the hex shaft.
4. Install the camshaft position sensor housing.
5. Install the camshaft position sensor housing studs. Tighten: Tighten the camshaft position sensor housing studs to 22 N.m (16 lb ft).
6. Install the underhood junction block. Refer to «Underhood Electrical Center or Junction Block Bracket Replacement»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management) in Wiring Systems.
7. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.

1. Remove the starter. Refer to «Starter Motor Replacement (2.2L (L61))»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (2.0L (LSJ))»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Disconnect the knock sensor (KS) harness connector.
3. Remove the KS retaining bolt.
4. Remove the KS.

1. Install the knock sensor. Tighten: Tighten the knock sensor retaining bolt to 25 N.m (18 lb ft).
2. Connect the knock sensor harness connector.
3. Install the starter. Refer to «Starter Motor Replacement (2.2L (L61))»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (2.0L (LSJ))»(/chevrolet/cobalt/i-2004-2010/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.

1. Disconnect the boost control solenoid connector.
2. Remove the boost control solenoid retaining bolt.
3. Remove the boost control solenoid (2).

1. Install the boost control solenoid (2) and bolt. Tighten: Tighten the bolt to 10 N.m (89 lb in).
2. Connect the boost control solenoid connector.

Scheme 29

Bypass Valve Actuator Replacement

1. Disconnect the barometric pressure (BARO) sensor harness connector.
2. Remove the BARO sensor bracket and bolt.
3. Remove the BARO sensor (2).

1. Install the BARO sensor (2).
2. Install the BARO sensor bracket and bolt. Tighten: Tighten the bolt to 10 N.m (89 lb in).
3. Connect the BARO sensor harness connector.

1. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .
2. Loosen the air cleaner cover screws (1).
3. Remove the air cleaner cover (2).
4. Remove the air cleaner filter from the air cleaner housing (3).

1. Install the air cleaner filter into the air cleaner housing.
2. Install the air cleaner cover to the air cleaner housing.
3. Install the air cleaner housing cover screws (3). Tighten: Tighten the air cleaner housing screws to 3 N.m (27 lb in).
4. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/cobalt/i-2004-2010/remont/testing-diagnostics/#engine-controls-20l-introduction) .

1. Remove the air cleaner outlet duct.
2. Remove the air cleaner assembly attachment fasteners.
3. Remove the air cleaner.

1. Position the air cleaner assembly.
2. Install the air cleaner assembly attachment bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
3. Connect the air cleaner resonator to the air cleaner assembly. Tighten: Tighten the air cleaner outlet duct clamps to 5 N.m (44 lb in).

1. Loosen the air cleaner assembly air duct at the outlet duct clamp 1.
2. Loosen the outlet duct clamp 2 at the throttle body.
3. Remove the air outlet duct.

1. Install the air outlet duct.
2. Install the air outlet duct clamps 1 and 2.
3. Tighten the air outlet duct clamps 1 and 2. Tighten: Tighten the clamps to 5 N.m (44 lb in).

1. Loosen the air cleaner assembly fresh air duct to resonator clamp.
2. Loosen the outlet resonator clamps.
3. Remove the air outlet resonator.

1. Install the air outlet resonator.
2. Tighten the air outlet resonator clamps. Tighten: Tighten the clamps to 5 N.m (44 lb in).

1. Remove the left front tire and wheel. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/cobalt/i-2004-2010/remont/wheel-tire-system/#tires-and-wheels) in Tire and Wheels.
2. Remove the left front fender liner. Refer to «Front Fender Liner Replacement»(/chevrolet/cobalt/i-2004-2010/remont/exterior-body-panels/#body-front-end) in Body Front End.
3. Remove the air cleaner intake duct assembly push-in fasteners.
4. Remove the air cleaner intake duct assembly bolt.
5. Remove the intake duct assembly from the vehicle.

1. Position the intake duct assembly.
2. Install the intake duct assembly bolt. Tighten: Tighten the bolt to 10 N.m (89 lb ft).
3. Install the intake duct assembly push in fasteners.
4. Install the left front fender liner. Refer to «Front Fender Liner Replacement»(/chevrolet/cobalt/i-2004-2010/remont/exterior-body-panels/#body-front-end) in Body Front End.
5. Install the left front tire and wheel. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/cobalt/i-2004-2010/remont/wheel-tire-system/#tires-and-wheels) in Tire and Wheels.

Powertrain

The powertrain has electronic controls to reduce exhaust emissions while maintaining excellent driveability and fuel economy. The powertrain control module (PCM) is the control center of this system. The PCM monitors numerous engine and vehicle functions. The PCM constantly looks at the information from various sensors and other inputs, and controls the systems that affect vehicle performance and emissions. The PCM also performs the diagnostic tests on various parts of the system. The PCM can recognize operational problems and alert the driver via the malfunction indicator lamp (MIL). When the PCM detects a malfunction, the PCM stores a diagnostic trouble code (DTC). The problem area is identified by the particular DTC that is set. The control module supplies a buffered voltage to various sensors and switches. Review the components and wiring diagrams in order to determine which systems are controlled by the PCM.

The following are some of the functions that the PCM controls

1. The engine fueling
2. The ignition control (IC)
3. The knock sensor (KS) system
4. The evaporative emissions (EVAP) system
5. The secondary air injection (AIR) system (if equipped)
6. The exhaust gas recirculation (EGR) system
7. The automatic transmission functions
8. The generator
9. The A/C clutch control
10. The cooling fan control

Powertrain Control Module Function

The powertrain control module (PCM) constantly looks at the information from various sensors and other inputs and controls systems that affect vehicle performance and emissions. The PCM also performs diagnostic tests on various parts of the system. The PCM can recognize operational problems and alert the driver via the malfunction indicator lamp (MIL). When the PCM detects a malfunction, the PCM stores a diagnostic trouble code (DTC). The problem area is identified by the particular DTC that is set. The control module supplies a buffered voltage to various sensors and switches. The input and output devices in the PCM include analog-to-digital converters, signal buffers, counters, and output drivers. The output drivers are electronic switches that complete a ground or voltage circuit when turned on. Most PCM controlled components are operated via output drivers. The PCM monitors these driver circuits for proper operation and, in most cases, can set a DTC corresponding to the controlled device if a problem is detected.

Malfunction Indicator Lamp (MIL) Operation

The malfunction indicator lamp (MIL) is located in the instrument panel cluster. The MIL will display as either SERVICE ENGINE SOON or one of the following symbols when commanded ON

Scheme 30

Scheme 31

The MIL indicates that an emissions related fault has occurred and vehicle service is required.

The following is a list of the modes of operation for the MIL

1. The MIL illuminates when the ignition is turned ON, with the engine OFF. This is a bulb test to ensure the MIL is able to illuminate.
2. The MIL turns OFF after the engine is started if a diagnostic fault is not present.
3. The MIL remains illuminated after the engine is started if the control module detects a fault. A diagnostic trouble code (DTC) is stored any time the control module illuminates the MIL due to an emissions related fault. The MIL turns OFF after three consecutive ignition cycles in which a Test Passed has been reported for the diagnostic test that originally caused the MIL to illuminate.
4. The MIL flashes if the control module detects a misfire condition which could damage the catalytic converter.
5. When the MIL is illuminated and the engine stalls, the MIL will remain illuminated as long as the ignition is ON.
6. When the MIL is not illuminated and the engine stalls, the MIL will not illuminate until the ignition is cycled OFF and then ON.

Trip

A trip is an interval of time during which the diagnostic test runs. A trip may consist of only a key cycle to power up the powertrain control module (PCM), allow the diagnostic to run, then cycle the key off to power down the PCM. A trip may also involve a PCM power up, meeting specific conditions to run the diagnostic test, then powering down the PCM. The definition of a trip depends upon the diagnostic. Some diagnostic tests run only once per trip (i.e., catalyst monitor) while other tests run continuously during each trip (i.e., misfire).

Warm-Up Cycle

The powertrain control module (PCM) uses warm-up cycles to run some diagnostics and to clear any diagnostic trouble codes (DTCs). A warm-up cycle occurs when the engine coolant temperature increases 22°C (40°F) from the start-up temperature. The engine coolant must also achieve a minimum temperature of 71°C (160°F). The PCM counts the number of warm-up cycles in order to clear the malfunction indicator lamp (MIL). The PCM will clear the DTCs when 40 consecutive warm-up cycles occur without a malfunction.

Diagnostic Trouble Codes (DTCs)

The powertrain control module (PCM) is programmed with test routines that test the operation of the various systems the PCM controls. Some tests monitor internal PCM functions. Many tests are run continuously. Other tests run only under specific conditions, referred to as Conditions for Running the DTC. When the vehicle is operating within the conditions for running a particular test, the PCM monitors certain parameters and determines if the values are within an expected range. The parameters and values considered outside the range of normal operation are listed as Conditions for Setting the DTC. When the Conditions for Setting the DTC occur, the PCM executes the Action Taken When the DTC Sets. Some DTCs alert the driver via the malfunction indicator lamp (MIL) or a message. Other DTCs do not trigger a driver warning, but are stored in memory. The PCM also saves data and input parameters when most DTCs are set. This data is stored in the Freeze Frame and/or Failure Records.

The DTCs are categorized by type. The DTC type is determined by the MIL operation and the manner in which the fault data is stored when a particular DTC fails. In some cases there may be exceptions to this structure. Therefore, when diagnosing the system it is important to read the Action Taken When the DTC Sets and the Conditions for Clearing the DTC in the supporting text.

There are different types of DTCs and different actions taken when the DTCs set. Refer to Diagnostic Trouble Code (DTC) Type Definitions for a description of the general characteristics of each DTC type.

DTC Status

When the scan tool displays a DTC, the status of the DTC is also displayed. The following DTC statuses are indicated only when they apply to the DTC that is set.

Description

The Eaton™ M 62 is a fifth generation Roots™-type supercharger. The supercharger is a positive displacement pump that consists of 2 counter-rotating rotors in a housing with an inlet port and an outlet port. The rotors are designed with 3 lobes and a helical 60° twist from front to back. An air bypass valve is built into the housing. The rotors in the supercharger are designed to run at a minimal clearance, not in contact with each other or the housing. The rotors are timed to each other by a pair of precision spur gears which are pressed onto the rotor shafts. The forward end of the rotors are held in position by deep-groove ball bearings. The back end of the rotors are supported by sealed roller bearings.

The gears and ball bearings are lubricated by a synthetic oil. The oil reservoir is self-contained in the supercharger and does not rely on engine oil for lubrication. This oil reservoir is sealed for the life of the unit and is not serviceable.

The cover on the supercharger contains the input shaft which is supported by 2, deep-groove ball bearings and is coupled to the rotor drive gears. The pulley is pressed onto the input shaft and is not serviceable. These bearings are lubricated by the synthetic oil contained in the same reservoir as the gears and rotor bearings.

Operation

The supercharger is designed to pump more air than the engine would normally use. This excess air creates a boost pressure in the intake manifold. Maximum engine boost is 83 kPa (12 psi). Because the supercharger is a positive displacement pump and is directly driven from the engine drive belt system, boost pressure is available at all driving conditions.

When boost is not desired, such as during idle and light throttle cruising, the excess air that the supercharger is producing is routed through the bypass passage between the intake manifold and the supercharger inlet. This bypass circuit is regulated by a bypass valve which is similar to a throttle plate. The bypass valve is controlled by a vacuum actuator which is connected to the vacuum signal between the throttle and the supercharger inlet. Spring force from the actuator holds the valve closed to create boost, and vacuum pulls the valve open when the throttle closes to decrease boost. The open bypass valve reduces pumping loss thereby increasing fuel efficiency.

The solenoid valve attached to the bypass actuator is an electronically controlled, 3-way valve. This valve, controlled by the powertrain control module (PCM), determines whether pressure from the manifold is routed to the bypass actuator or closed off. The valve allows pressure from the manifold to open the bypass valve and regulate boost pressure during specific driving conditions.

Intercooler

The supercharger has an integrated intercooler. Cooling the air enhances the effectiveness of the supercharger. The intercooler uses conventional coolant in a separate sealed system from the engine cooling system. The intercooler system has a radiator, a reserve tank/filler neck, a pressure cap, attaching hoses, and a pump capable of a 26 liters (7 gallons) per minute flow rate. The pump is commanded ON, by the control module, whenever the engine is running.

Fuel System Overview

The fuel tank stores the fuel supply. An electric turbine style fuel pump attaches to the fuel sender assembly inside the fuel tank. The fuel pump supplies high pressure fuel through the fuel filter and the fuel feed pipe to the fuel injection system. The fuel pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pump also supplies fuel to a venturi pump located on the bottom of the fuel sender assembly. The function of the venturi pump is to fill the fuel sender assembly reservoir. The fuel pressure regulator, a part of the fuel sender assembly, maintains the correct fuel pressure to the fuel injection system. The fuel pump and sender assembly contains a reverse flow check valve. The check valve and the fuel pressure regulator maintain fuel pressure in the fuel feed pipe and the fuel rail in order to prevent long cranking times.

Fuel Tank

The fuel tank stores the fuel supply. The fuel tank is located in the rear of the vehicle. The fuel tank is held in place by 2 metal straps that attach to the under body of the vehicle. The fuel tank is molded from high-density polyethylene.

Fuel Fill Pipe

The fuel fill pipe has a built-in restrictor in order to prevent refueling with leaded fuel.

Fuel Filler Cap

Note. If a fuel tank filler cap requires replacement, use only a fuel tank filler cap with the same features. Failure to use the correct fuel tank filler cap can result in a serious malfunction of the fuel and EVAP system.

The fuel fill pipe has a tethered fuel filler cap. A torque-limiting device prevents the cap from being over-tightened. To install the cap, turn the cap clockwise until you hear audible clicks. This indicates that the cap is correctly torqued and fully seated. A fuel filler cap that is not fully seated may cause a malfunction in the emission system.

Fuel Sender Assembly

The fuel sender assembly consists of the following major components

1. The fill limit vent valve
2. The fuel level sensor
3. The fuel tank pressure (FTP) sensor
4. The fuel pump
5. The fuel pressure regulator
6. The fuel strainer

Fuel Level Sensor

The fuel level sensor consists of a float, a wire float arm, and a ceramic resistor card. The position of the float arm indicates the fuel level. The fuel level sensor contains a variable resistor which changes resistance in correspondence with the position of the float arm. The powertrain control module (PCM) sends the fuel level information via the GMLAN serial data circuit to the body control module (BCM). The BCM sends the GMLAN message to the instrument panel cluster (IPC). This information is used for the IPC fuel gage and the low fuel warning indicator, if applicable. The PCM also monitors the fuel level input for various diagnostics.

Fuel Pump

The fuel pump is mounted in the fuel sender assembly reservoir. The fuel pump is an electric high-pressure pump. Fuel is pumped to the fuel injection system at a specified flow and pressure. The fuel pump delivers a constant flow of fuel to the engine even during low fuel conditions and aggressive vehicle maneuvers. The control module controls the electric fuel pump operation through a fuel pump relay. The fuel pump flex pipe acts to dampen the fuel pulses and noise generated by the fuel pump.

Fuel Strainer

The fuel strainer attaches to the lower end of the fuel sender. The fuel strainer is made of woven plastic. The functions of the fuel strainer are to filter contaminants and to wick fuel. The fuel strainer normally requires no maintenance. Fuel stoppage at this point indicates that the fuel tank contains an abnormal amount of sediment or contamination.

Fuel Filter

The fuel filter is located on the fuel feed pipe between the fuel pump and the fuel injectors. The paper filter element traps particles in the fuel that may damage the fuel injection system. The filter housing is made to withstand maximum fuel system pressure, exposure to fuel additives, and changes in temperature. There is no service interval for fuel filter replacement.

Fuel Pressure Regulator

The fuel pressure regulator is contained in the fuel sender assembly. The fuel pressure regulator is a diaphragm relief valve. The diaphragm has fuel pressure on one side and regulator spring pressure on the other side. Fuel pressure is controlled by a pressure balance across the regulator. The fuel system pressure is constant and is no longer a function of engine load or manifold vacuum. A software bias compensates the injector on-time based on the signal from the manifold absolute pressure (MAP) sensor.

Fuel Feed Pipes

The fuel feed pipe carries fuel from the fuel tank to the fuel injection system. The fuel pipe consists of 3 sections

1. The rear fuel pipe is located from the top of the fuel tank to the chassis fuel pipe. The rear fuel pipe is constructed of nylon.
2. The chassis fuel pipe is located under the vehicle and connects the rear fuel pipe to the engine compartment fuel pipe. The chassis fuel pipe is constructed of galvanized aluminum.
3. The engine compartment fuel pipe connects the chassis fuel feed pipe to the fuel rail. The engine compartment fuel pipe is constructed of steel.

Nylon Fuel Pipes

Nylon pipes are constructed to withstand maximum fuel system pressure, exposure to fuel additives, and changes in temperature.

Heat resistant rubber hose or corrugated plastic conduit protect the sections of the pipes that are exposed to chafing, high temperature, or vibration.

Nylon fuel pipes are somewhat flexible and can be formed around gradual turns under the vehicle. However, if nylon fuel pipes are forced into sharp bends, the pipes kink and restrict the fuel flow. Also, once exposed to fuel, nylon pipes may become stiffer and are more likely to kink if bent too far. Take special care when working on a vehicle with nylon fuel pipes.

Quick-Connect Fittings

Quick-connect fittings provide a simplified means of installing and connecting fuel system components. The fittings consist of a unique female connector and a compatible male pipe end. O-rings, located inside the female connector, provide the fuel seal. Integral locking tabs inside the female connector hold the fittings together.

Fuel Pipe O-rings

O-rings seal the threaded connections in the fuel system. The fuel system O-ring seals are made of special material. Service the O-ring seals with the correct service part.

Scheme 32

The fuel rail assembly attaches to the cylinder head. The fuel rail assembly performs the following functions

1. Positions the injectors in the cylinder head
2. Distributes fuel evenly to the injectors
3. Integrates the fuel pulse dampener into the fuel metering system

Scheme 33

The fuel injector assembly is a solenoid device controlled by the control module that meters pressurized fuel to a single engine cylinder. The control module energizes the high-impedance, 12 ohm, injector solenoid (4) to open a normally closed ball valve (1). This allows fuel to flow into the top of the injector, past the ball valve, and through a director plate (3) at the injector outlet. The director plate has machined holes that control the fuel flow, generating a spray of finely atomized fuel at the injector tip. Fuel from the injector tip is directed at the intake valve, causing the fuel to become further atomized and vaporized before entering the combustion chamber. This fine atomization improves fuel economy and emissions.

Scheme 34

The fuel pulse dampener attaches inside a housing on the fuel rail assembly. The fuel pulse dampener is diaphragm-operated, with fuel pump pressure on one side and with spring pressure on the other side. The function of the dampener is to dampen the fuel pump pressure pulsations.

Fuel Metering Modes of Operation

The control module monitors voltages from several sensors in order to determine how much fuel to give the engine. The control module controls the amount of fuel delivered to the engine by changing the fuel injector pulse width. The fuel is delivered under one of several modes.

Starting Mode

When the ignition is first turned ON, the control module energizes the fuel pump relay for 2 seconds. This allows the fuel pump to build pressure in the fuel system. The control module calculates the air/fuel ratio based on inputs from the engine coolant temperature (ECT), manifold absolute pressure (MAP), and throttle position (TP) sensors. The system stays in starting mode until the engine speed reaches a predetermined RPM.

Clear Flood Mode

If the engine floods, clear the engine by pressing the accelerator pedal down to the floor and then crank the engine. When the throttle position (TP) sensor is at wide open throttle (WOT), the control module reduces the fuel injector pulse width in order to increase the air to fuel ratio. The control module holds this injector rate as long as the throttle stays wide open and the engine speed is below a predetermined RPM. If the throttle is not held wide open, the control module returns to the starting mode.

Run Mode

The run mode has 2 conditions called Open Loop and Closed Loop. When the engine is first started and the engine speed is above a predetermined RPM, the system begins Open Loop operation. The control module ignores the signal from the heated oxygen sensor (HO2S). The control module calculates the air/fuel ratio based on inputs from the engine coolant temperature (ECT), manifold absolute pressure (MAP), and throttle position (TP) sensors. The system stays in Open Loop until meeting the following conditions

1. The HO2S has varying voltage output, showing that the HO2S is hot enough to operate properly.
2. The ECT sensor is above a specified temperature.
3. A specific amount of time has elapsed after starting the engine.

Specific values for the above conditions exist for this engine, and are stored in the electrically erasable programmable read-only memory (EEPROM). The system begins Closed Loop operation after reaching these values. In Closed Loop, the control module calculates the air/fuel ratio, injector ON time, based upon the signal from various sensors, but mainly from the HO2S. This allows the air/fuel ratio to stay very close to 14.7:1.

Acceleration Mode

When the driver pushes on the accelerator pedal, air flow into the cylinders increases rapidly. To prevent possible hesitation, the control module increases the pulse width to the injectors to provide extra fuel during acceleration. This is also known as power enrichment. The control module determines the amount of fuel required based upon the throttle position (TP), the engine coolant temperature (ECT), the manifold absolute pressure (MAP), and the engine speed.

Deceleration Mode

When the driver releases the accelerator pedal, air flow into the engine is reduced. The control module monitors the corresponding changes in the throttle position (TP) and the manifold absolute pressure (MAP). The control module shuts OFF fuel completely if the deceleration is very rapid, or for long periods, such as long, closed-throttle coast-down. The fuel shuts OFF in order to prevent damage to the catalytic converters.

Battery Voltage Correction Mode

When the battery voltage is low, the control module compensates for the weak spark delivered by the ignition system in the following ways

1. Increasing the amount of fuel delivered
2. Increasing the idle RPM
3. Increasing the ignition dwell time

Fuel Cutoff Mode

The control module cuts OFF fuel from the fuel injectors when the following conditions are met in order to protect the powertrain from damage and improve driveability

1. The ignition is OFF. This prevents engine run-on.
2. The ignition is ON but there is no ignition reference signal. This prevents flooding or backfiring.
3. The engine speed is too high, above red line.
4. The vehicle speed is too high, above rated tire speed.
5. During an extended, high speed, closed throttle coast down-This reduces emissions and increases engine braking.
6. During extended deceleration, in order to prevent damage to the catalytic converters

Fuel Trim

The control module controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. The control module monitors the heated oxygen sensor (HO2S) signal voltage while in Closed Loop and regulates the fuel delivery by adjusting the pulse width of the injectors based on this signal. The ideal fuel trim values are around 0 percent for both short and long term fuel trim. A positive fuel trim value indicates the control module is adding fuel in order to compensate for a lean condition by increasing the pulse width. A negative fuel trim value indicates that the control module is reducing the amount of fuel in order to compensate for a rich condition by decreasing the pulse width. A change made to the fuel delivery changes the long and short term fuel trim values. The short term fuel trim values change rapidly in response to the HO2S signal voltage. These changes fine tune the engine fueling. The long term fuel trim makes coarse adjustments to fueling in order to re-center and restore control to short term fuel trim. A scan tool can be used to monitor the short and long term fuel trim values. The long term fuel trim diagnostic is based on an average of several of the long term speed load learn cells. The control module selects the cells based on the engine speed and engine load. If the control module detects an excessively lean or rich condition, the control module will set a fuel trim diagnostic trouble code (DTC).

EVAP System Operation

The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister. Carbon in the canister absorbs and stores the fuel vapors. Excess pressure is vented through the vent line and EVAP vent solenoid valve to the atmosphere. The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the control module will command the EVAP purge solenoid valve ON, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent solenoid valve OFF, fresh air is drawn through the vent solenoid valve and the vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge solenoid valve into the intake manifold to be consumed during normal combustion. The control module uses several tests to determine if the EVAP system is leaking.

Large Leak Test

This tests for large leaks and blockages in the evaporative emission (EVAP) system. The control module commands the EVAP vent solenoid valve ON and commands the EVAP purge solenoid valve ON, with the engine running, allowing engine vacuum into the EVAP system. The control module monitors the fuel tank pressure (FTP) sensor voltage to verify that the system is able to reach a predetermined level of vacuum within a set amount of time. The control module then commands the EVAP purge solenoid valve OFF, sealing the system, and monitors the vacuum level for decay. If the control module does not detect that the predetermined vacuum level was achieved, or the vacuum decay rate is more than a calibrated level on 2 consecutive tests, DTC P0455 will set.

Small Leak Test

The engine off natural vacuum (EONV) diagnostic is the small-leak detection diagnostic for the evaporative emission (EVAP) system. While previous leak detection methods were performed with the engine running, the EONV diagnostic monitors the EVAP system pressure or vacuum with the ignition OFF. Because of this, it may be normal for the control module to remain active for up to 40 minutes after the ignition is turned OFF. This is important to remember when performing a parasitic draw test on vehicles equipped with EONV.

The EONV utilizes the temperature changes in the fuel tank immediately following a drive cycle to use the naturally occurring vacuum or pressure in the fuel tank. When the vehicle is driven, the temperature rises in the tank. After the vehicle is parked, the temperature in the tank continues to rise for a period of time, then starts to drop. The EONV diagnostic relies on this temperature change and the corresponding pressure change in a sealed system, to determine if an EVAP system leak is present.

The EONV diagnostic is designed to detect leaks as small as 0.51 mm (0.020 in). The diagnostic can determine if a small leak is present based on vacuum or pressure readings in the EVAP system. When the system is sealed, a finite amount of pressure or vacuum will be observed. When a 0.51 mm (0.020 in) leak is present, often little or no pressure or vacuum is observed. If the test reports a failing value, DTC P0442 will set.

Canister Vent Restriction Test

If the evaporative emission (EVAP) vent system is restricted, fuel vapors will not be properly purged from the EVAP canister. The control module tests this by commanding the EVAP purge solenoid valve ON, commanding the EVAP vent solenoid valve OFF, and monitoring the fuel tank pressure (FTP) sensor for an increase in vacuum. If the vacuum increases more than a calibrated value, DTC P0446 will set.

Purge Solenoid Valve Leak Test

If the evaporative emission (EVAP) purge solenoid valve does not seal properly fuel vapors could enter the engine at an undesired time, causing driveability concerns. The control module tests for this by commanding the EVAP purge solenoid valve OFF and the vent solenoid valve ON, sealing the system, and monitors the fuel tank pressure (FTP) for an increase in vacuum. If the control module detects that the EVAP system vacuum increases above a calibrated value, DTC P0496 will set.

Check Gas Cap Message

The powertrain control module (PCM) sends a class 2 message to the driver information center (DIC) illuminating the Check Gas Cap message when any of the following occur

1. A malfunction in the evaporative emission (EVAP) system and a large leak test fails
2. A malfunction in the EVAP system and a small leak test fails

EVAP System Components

The evaporative emission (EVAP) system consists of the following components

EVAP Canister

The canister is filled with carbon pellets used to absorb and store fuel vapors. Fuel vapor is stored in the canister until the control module determines that the vapor can be consumed in the normal combustion process.

EVAP Purge Solenoid Valve

The EVAP purge solenoid valve controls the flow of vapors from the EVAP system to the intake manifold. The purge solenoid valve opens when commanded ON by the control module. This normally closed valve is pulse width modulated (PWM) by the control module to precisely control the flow of fuel vapor to the engine. The valve will also be opened during some portions of the EVAP testing, allowing engine vacuum to enter the EVAP system.

EVAP Vent Solenoid Valve

The EVAP vent solenoid valve controls fresh airflow into the EVAP canister. The valve is normally open. The control module commands the valve ON, closing the valve during some EVAP tests, allowing the system to be tested for leaks.

Fuel Tank Pressure Sensor

The fuel tank pressure (FTP) sensor measures the difference between the pressure or vacuum in the fuel tank and outside air pressure. The control module provides a 5-volt reference and a ground to the FTP sensor. The FTP sensor provides a signal voltage back to the control module that can vary between 0.1-4.9 volts. A high FTP sensor voltage indicates a low fuel tank pressure or vacuum. A low FTP sensor voltage indicates a high fuel tank pressure.

EVAP Service Port

The EVAP service port is located in the EVAP purge pipe between the EVAP purge solenoid valve and the EVAP canister. The service port is identified by a green colored cap.

Electronic Ignition (EI) System Operation

The electronic ignition (EI) system produces and controls the high energy secondary spark. This spark ignites the compressed air/fuel mixture at precisely the correct time, providing optimal performance, fuel economy, and control of exhaust emissions. The powertrain control module (PCM) primarily collects information from the crankshaft position (CKP) and camshaft position (CMP) sensors to control the sequence, dwell, and timing of the spark.

Crankshaft Position (CKP) Sensor

The crankshaft position (CKP) sensor is a permanent magnet generator known as a variable reluctance sensor. The CKP sensor produces an AC voltage of varying amplitude and frequency. The frequency depends on the velocity of the crankshaft. The AC output depends on the crankshaft position and the battery voltage. The CKP sensor works in conjunction with a 58-tooth reluctor wheel attached to the crankshaft. As each reluctor wheel tooth rotates past the CKP sensor, the resulting change in the magnetic field creates an ON/OFF pulse 58 times per crankshaft revolution. The PCM processes the pulses to create a pattern that enables the PCM to determine the crankshaft position. The PCM can synchronize the ignition timing, the fuel injector timing, and the spark knock control based on the CKP sensor and the camshaft position (CMP) sensor inputs. The CKP sensor is also used to detect misfire and for tachometer display. The PCM learns the variations between all 58 teeth under different speed and load conditions to correctly detect misfires. The CKP sensor circuits consist of a signal circuit and a low reference circuit. The two wires are twisted together to prevent electromagnetic interference on the CKP sensor circuits.

Crankshaft Reluctor Wheel

The crankshaft reluctor wheel is part of the crankshaft. The reluctor wheel consists of 58 teeth and a reference gap. Each tooth on the reluctor wheel is spaced 6 degrees apart with a 12-degree space for the reference gap. The pulse from the reference gap is known as the sync pulse. The sync pulse is used to synchronize the coil firing sequence with the crankshaft position, while the other teeth provide cylinder location during a revolution.

Camshaft Position (CMP) Sensor

The camshaft position (CMP) sensor is triggered by a notched reluctor wheel built onto the exhaust camshaft sprocket. The CMP sensor provides four signal pulses every camshaft revolution. Each notch, or feature of the reluctor wheel is of a different size which is used to identify the compression stroke of each cylinder and to enable sequential fuel injection. The CMP sensor is connected to the PCM by the following circuits

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

Ignition Coil/Module

Each ignition coil/module has the following circuits

1. An ignition voltage circuit
2. A ground
3. An ignition control (IC) circuit
4. A low reference circuit

The PCM controls the individual coils by transmitting timing pulses on the IC circuit of each ignition coil/module to enable a spark event.

The spark plugs are connected to each coil by a short boot. The boot contains a spring that conducts the spark energy from the coil to the spark plug. The spark plug electrode is tipped with platinum for long wear and higher efficiency.

Powertrain Control Module (PCM)

The PCM controls all ignition system functions, and constantly corrects the spark timing. The PCM monitors information from various sensor inputs that include the following

1. The throttle position (TP) sensor
2. The engine coolant temperature (ECT) sensor
3. The mass air flow (MAF) sensor
4. The intake air temperature (IAT) sensor
5. The vehicle speed sensor (VSS)
6. The engine knock sensor (KS)

Modes of Operation

During normal operation the PCM controls all ignition functions. If either the CKP or CMP sensor signal is lost, the engine will continue to run because the PCM will default to a limp home mode using the remaining sensor input. As mentioned above, each coil is internally protected against damage from excessive voltage. If one or more coils were to fail in this manner, a misfiring condition would result. Diagnostic trouble codes are available to accurately diagnose the ignition system with a scan tool.

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Supercharger boost pressure is regulated to prevent engine and drive train damage. When the engine is operating under high boost conditions, the powertrain control module (PCM) limits boost pressure to 83 kPa (12 psi). The PCM disables boost under the following conditions

1. When reverse gear is selected
2. When the engine coolant temperature (ECT) is excessively high
3. When drivetrain abuse is detected
4. When the vehicle is decelerating
5. If an intercooler pump failure is detected
6. If the intake air temperature (IAT) sensor 2 becomes excessively high
7. Under heavy load in first and second gear at engine speeds above 5,800 RPM

The PCM controls boost pressure by using the boost control solenoid. The boost control solenoid is normally an open valve. Under most conditions, the PCM commands the boost control solenoid to operate at a 99-100 percent duty cycle. This keeps the solenoid valve closed and allows only inlet vacuum to control the position of the bypass valve. At idle, engine vacuum is applied to the upper side of the bypass valve actuator, counteracting spring tension to hold the bypass valve open. As engine load is increased, engine vacuum is decreased, causing the spring in the bypass valve actuator to overcome the applied vacuum, closing the bypass valve and allowing the boost pressure to increase. The bypass valve starts to close when the vacuum measures 250 mm Hg (10 in Hg) and is fully closed at 90 mm Hg (3.5 in Hg). When reduced boost pressure is desired, the PCM commands the boost control solenoid to operate at a 0 percent duty cycle. This opens the solenoid valve and allows boost pressure to enter the bypass valve actuator at the lower side to counteract the spring tension, opening the bypass valve and recirculating excess boost pressure back into the supercharger inlet.

Results of Incorrect Operation

An open boost control solenoid control circuit, an open ignition 1 circuit, or boost control solenoid valve stuck open will cause reduced engine power, especially during wide open throttle operation.

The boost control solenoid control circuit shorted to ground, boost control solenoid valve stuck closed or a restriction in the boost source or signal hoses will cause full boost to be commanded at all times and a possible overboost condition during high engine load situations.

A restriction in the vacuum signal hose to the bypass valve actuator or a stuck closed bypass valve will cause a rough idle and reduced fuel economy.

Purpose

The throttle actuator control (TAC) system delivers improved throttle response and greater reliability and eliminates the need for mechanical cable. The TAC system performs the following functions

1. Accelerator pedal position (APP) sensing
2. Throttle positioning to meet driver and engine demands
3. Throttle position (TP) sensing
4. Internal diagnostics
5. Cruise control functions
6. Manage TAC electrical power consumption

The TAC system includes the following components

1. The APP sensors
2. The throttle body assembly
3. The powertrain control module (PCM)

Accelerator Pedal Position (APP) Sensor

The accelerator pedal contains 2 individual accelerator pedal position (APP) sensors within the assembly. The APP sensors 1 and 2 are potentiometer type sensors each with 3 circuits

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

The APP sensors are used to determine the pedal angle. The powertrain control module (PCM) provides each APP sensor a 5-volt reference circuit and a low reference circuit. The APP sensors provide the PCM with signal voltage proportional to the pedal movement. The APP sensor 1 signal voltage at rest position is near the low reference and increases as the pedal is actuated. The APP sensor 2 signal voltage at rest position is near the 5-volt reference and decreases as the pedal is actuated.

Throttle Body Assembly

The throttle assembly contains the following components

1. The throttle blade
2. The throttle actuator motor
3. The throttle position (TP) sensor 1 and 2

The throttle body functions similar to a conventional throttle body with the following exceptions

1. An electric motor opens and closes the throttle valve.
2. The throttle blade is spring loaded in both directions and the default position is slightly open.
3. There are 2 individual TP sensors within the throttle body assembly.

The TP sensors are used to determine the throttle plate angle. The TP sensors provide the powertrain control module (PCM) with a signal voltage proportional to throttle plate movement. The TP sensor 1 signal voltage at closed throttle is near the 5-volt reference and decreases as the throttle plate is opened. The TP sensor 2 signal voltage at closed throttle is near the low reference and increases as the throttle plate is opened.

Powertrain Control Module

The powertrain control module (PCM) is the control center for the throttle actuator control (TAC) system. The PCM determines the drivers intent and then calculates the appropriate throttle response. The PCM achieves throttle positioning by providing a pulse width modulated voltage to the TAC motor.

Normal Mode

During the operation of the throttle actuator control (TAC) system, several modes or functions are considered normal. The following modes may be entered during normal operation

1. Minimum pedal value-At key-up the powertrain control module (PCM) updates the learned minimum pedal value.
2. Minimum throttle position (TP) values-At key-up the PCM updates the learned minimum TP value. In order to learn the minimum TP value, the throttle blade is moved to the closed position.
3. Ice break mode-If the throttle is not able to reach a predetermined minimum TP, the ice break mode is entered. During the ice break mode, the PCM commands the maximum pulse width several times to the throttle actuator motor in the closing direction.
4. Battery saver mode-After a predetermined time without engine RPM, the PCM commands the battery saver mode. During the battery saver mode, the TAC module removes the voltage from the motor control circuits, which removes the current draw used to maintain the idle position and allows the throttle to return to the spring loaded default position.

Reduced Engine Power Mode

When the PCM detects a condition with the TAC system, the PCM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions

1. Acceleration limiting-The PCM will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.
2. Limited throttle mode-The PCM will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.
3. Throttle default mode-The PCM will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.
4. Forced idle mode-The PCM will perform the following actions: Limit engine speed to idle by positioning the throttle position, or by controlling the fuel and spark if the throttle is turned OFF. Ignore the accelerator pedal input.
5. Engine shutdown mode-The PCM will disable fuel and de-energize the throttle actuator.

The knock sensor (KS) system enables the engine control module (ECM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The ECM uses the KS system to test for abnormal engine noise that may indicate detonation, also known as spark knock.

Sensor Description

The KS system uses a flat response two-wire sensor. The sensor uses piezo-electric crystal technology that produces an AC voltage signal of varying amplitude and frequency based on the engine vibration, or noise, level. The amplitude and frequency are dependent upon the level of knock that the KS detects. The ECM receives the KS signal through a signal circuit. The KS ground is supplied by the ECM through a low reference circuit.

The ECM learns a minimum noise level, or background noise, at idle from the KS and uses calibrated values for the rest of the RPM range. The ECM uses the minimum noise level to calculate a noise channel. A normal KS signal will ride within the noise channel. As engine speed and load change, the noise channel upper and lower parameters will change to accommodate the KS signal, keeping the signal within the channel. In order to determine which cylinders are knocking, the ECM only uses KS signal information when each cylinder is near top dead center (TDC) of the firing stroke. If knock is present, the signal will range outside of the noise channel.

If the ECM has determined that knock is present, it will retard the ignition timing to attempt to eliminate the knock. The ECM will always try to work back to a zero compensation level, or no spark retard. An abnormal KS signal will stay outside of the noise channel or will not be present. KS diagnostics are calibrated to detect faults with the KS circuitry inside the ECM, the KS wiring, the KS voltage output, or constant noise from an outside influence such as a loose/damaged component or excessive engine mechanical noise.

Air Intake System Description

The primary function of the Air Intake System is to provide filtered air to the engine. The system uses a cleaner element mounted in a housing. The cleaner housing is remotely mounted and uses intake ducts to route the incoming air into the throttle body. The secondary function of the Air Intake System is to muffle air induction noise. This is achieved through the use of resonators attached to the air intake ducts. The resonators are tuned to the specific powertrain. The mass air flow (MAF)/intake air temperature (IAT) sensor is used to measure the temperature and the volume of the air entering the engine.

Special Tools

Special Tools Illustration Tool Number/ Description GE 41415-50 Fuel Tank Cap Adapter J 26792 Spark Tester J 34730-1A Fuel Pressure Gage J 35616-A GM Terminal Test Kit J 36012-A Ignition System Diagnostic Harness J 37027-1A IAC Motor Driver You may also use an IAC Motor Driver from one of the approved manufacturers listed below: OTC Thexton CTI Snap On MAC Tools NAPA/Balkamp J 37088-A Fuel Line Disconnect Tool Set J 37287 Fuel Pipe Shut-Off Adapter J 38500-A Fuel Injector Cleaner J 38522 Variable Signal Generator J 39021 Fuel Injector Tester J 39194-C Oxygen Sensor Wrench J 39765 Fuel Sender Lock Nut Wrench J 41413-200 Evaporative Emissions System Tester (EEST) J 41413-VLV EVAP Service Port Vent Fitting J 41413-SPT High Intensity White Light J 41415-40 Fuel Tank Cap Adapter J 41416 Ultrasonic Leak Detector J 42873-1 Fuel Line Shut-Off Adapter J 42873-2 Fuel Line Shut-Off Adapter J 42960-1 Fuel Drain Hose J 42960-2 Fuel Flapper Door Holder J 42964-1 Fuel Line Shut-Off Adapter J 42964-2 Fuel Line Shut-Off Adapter J 43244 Relay Puller Pliers J 43298 Ignition Module Tester J 44175 Fuel Composition Tester J 45004 Fuel Tank Drain Hose J 45722 Fuel Sender Lock Ring Wrench 7000061 Tech II Diagnostic Scan Tool

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See also:
• Battery Negative Cable Disconnect/Connect Procedure
• Control Module References
• Diagnostic Trouble Code (DTC) List - Vehicle
• DTC P0315
• Draining and Filling Cooling System (2.0L (LSJ))
• Fastener Notice
• Lifting and Jacking the Vehicle
• Tire and Wheel Removal and Installation
• Front Fender Liner Replacement
• Splash Shield Replacement - Engine
• Exhaust Manifold Replacement (L61)
• Heated Oxygen and Oxygen Sensor Notice
• Excessive Force and Oxygen Sensor Notice
• Component Fastener Tightening Notice
• Gasoline/Gasoline Vapors Caution
• Fuel Filler Pocket Replacement
• Fuel Sender Assembly Replacement
• Underhood Electrical Center or Junction Block Bracket Replacement
• Fastener Tightening Specifications
• Special Tools
• Air Cleaner Outlet Resonator Replacement
• Ignition System Specifications
• Spark Plug Inspection
• CKP System Variation Learn Procedure