Engine Control System (Introduction) - 2.2l (l61) Chevrolet Malibu VI

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

Action Taken When the DTC Sets - Type A

The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.

Action Taken When the DTC Sets - Type B

The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.

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. 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 driver information center, if equipped, may display a message.

Conditions for Clearing the DTC - Type C

1. A last test failed, or current DTC, clears when the diagnostic runs and passes.
2. Use a scan tool in order to clear the DTC.

Conditions for Clearing the DTC - Type X

This DTC is available in the PCM software, but has been disabled, or turned OFF. In this case, the diagnostic does not run, no DTCs are stored, and the MIL does not illuminate. Type X DTCs are used primarily for export vehicles that do not require MIL illumination or DTC storing.

Diagnostic Trouble Code (DTC) Type(s)

Diagnostic Trouble Code (DTC) Type(s)

Scheme 67

Scheme 68

Scheme 69

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)

Scheme 70

Scheme 71

Engine Controls Schematics

Refer to SYSTEM WIRING DIAGRAMS .

Scheme 72

Scheme 73

Scheme 74

Scheme 75

Scheme 76

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Scheme 78

Scheme 79

Scheme 80

Scheme 81

Scheme 82

Scheme 83

Powertrain Control Module (PCM) Connector End Views

Powertrain Control Module (PCM) C1 Connector End Connector Part Information 15430210 56-Way F Micro-Pack 64 Series Sealed (BU) Pin Wire Color Circuit No. Function 1 TN/BK 2500 High Speed GMLAN Serial Data (+) 2 TN 2501 High Speed GMLAN Serial Data (-) 3-5 - - Not Used 6 D-GN/WH 459 A/C Compressor Clutch Relay Control 7 BN 1271 Low Reference 8 TN 1274 5-Volt Reference 9 - - Not Used 10 D-GN 335 Low Speed Cooling Fan Relay Control 11 - - Not Used 12 PU 1589 Fuel Level Sensor Signal 13 PK/BK 5290 Ignition 1 Voltage 14 - - Not Used 15 PU 1807 Class 2 Serial Data 16 - - Not Used 17 GY 2700 5-Volt Reference 18 BN 4 Accessory Voltage 19 PK 639 Ignition 1 Voltage 20 RD/WH 540 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 APP Sensor 1 Signal 28 - - Not Used 29 OG/BK 1057 Low Reference 30 WH/BK 1164 5-Volt Reference 31 - - Not Used 32 WH 17 Stop Lamp Switch Signal 33-36 - - Not Used 37 D-GN/WH 465 Fuel Pump Relay Control 38 BN 5069 Main Relay Control 39 - - Not Used 40 BN/WH 419 MIL Control 41 L-BU 1162 APP Sensor 2 Signal 42 - - Not Used 43 PU 1272 Low Reference 44 - - Not Used 45 PU 5526 Tap Up/Tap Down Switch Signal 46 - - Not Used 47 GY 705 5-Volt Reference 48 YE 447 Starter Relay Coil Control 49-50 - - Not Used 51 D-BU 473 High Speed Cooling Fan Relay Control 52-53 - - Not Used 54 PU/WH 1035 Starter Relay Coil Supply Voltage 55 OG/BK 1057 Low Reference 56 TN 5514 Low Reference

Powertrain Control Module (PCM) C2 Connector End Connector Part Information 15430225 73-Way F Micro 64 Series Sealed (BK) Pin Wire Color Circuit No. Function 1 OG 225 Generator Turn On Signal 2 D-GN 485 TP Sensor 1 Signal 3-5 - - Not Used 6 GY 2701 5-Volt Reference 7 PU 486 TP Sensor 2 Signal 8 GY 2704 5-Volt Reference 9 L-BU/BK 1688 5-Volt Reference 10-16 - - Not Used 17 YE 573 Crankshaft Position Sensor Signal (1) 18 PU 574 Crankshaft Position Sensor Low Reference (1) 19 - - Not Used 20 OG/BK 469 CKP Sensor B Signal 21-24 - - Not Used 25 TN/WH 3121 HO2S Low Signal Bank 1 Sensor 2 26 BN/WH 633 Camshaft Position Signal 27-31 - - Not Used 32 TN/WH 3111 HO2S Low Reference Bank 1 Sensor 1 33 TN 1744 Fuel Injector 1 Control 34 - - Not Used 35 YE 410 ECT Sensor Signal 36 TN/WH 1704 Low Reference 37 L-GN 432 MAP Sensor Signal 38 - - Not Used 39 TN 2752 Low Reference 40 WH 423 IC Timing Control 41 YE 492 MAF Sensor Signal 42 - - Not Used 43 GY/WH 3122 HO2S Heater Low Control Sensor 1 44 - - Not Used 45 GY 23 Generator Field Duty Cycle Signal 46 PU 3120 HO2S High Signal Sensor 2 47 - - Not Used 48 PU/WH 3110 HO2S Reference Voltage Sensor 1 49-50 - - Not Used 51 TN 472 IAT Sensor Signal 52 TN 2761 Low Reference 53 PK/BK 1746 Fuel Injector 3 Control 54 L-GN/BK 1745 Fuel Injector 2 Control 55 L-BU/BK 844 Fuel Injector 4 Control 56-57 - - Not Used 58 GY/WH 3113 HO2S Heater Low Control Sensor 1 59 OG 406 IC Timing Control B 60-63 - - Not Used 64 TN/BK 2760 Low Reference 65 BN 582 TAC Motor Control 2 66 YE 581 TAC Motor Control 1 67 - - Not Used 68 D-BU 496 Knock Sensor Signal 69 GY 1716 Low Reference 70-72 - - Not Used 73 BK/WH 451 Ground

Powertrain Control Module (PCM) C3 Connector End Connector Part Information 15430209 56-Way F Micro 64 Series Sealed (GY) Pin Wire Color Circuit No. Function 1 - - Not Used 2 GY 773 Transmission Range Switch Signal C 3-5 - - Not Used 6 OG/BK 1228 PC Solenoid Valve High Control (Sol. A) 7 YE/BK 1227 TFT Sensor Signal 8-10 - - Not Used 11 OG/BK 1230 AT ISS High Signal 12-14 - - Not Used 15 TN/BK 231 Oil Pressure Switch Signal 16 - - Not Used 17 TN 2762 Low Reference 18-19 - - Not Used 20 TN/WH 771 Transmission Range Switch Signal A 21-28 - - Not Used 29 YE 657 Transmission Fluid Pressure Sensor Signal 30 OG 1226 Transmission Fluid Pressure Switch Signal C 31-32 - - Not Used 33 L-GN 1222 Shift Solenoid Valve 1 High Control 34 - - Not Used 35 YE/BK 1223 Shift Solenoid Valve 2 High Control 36 - - Not Used 37 D-GN/WH 428 EVAP Canister Purge Solenoid Control 39 BN 418 TCC PWM Solenoid Valve Control 40-42 - - Not Used 43 D-BU 1225 Transmission Fluid Pressure Switch Signal B 44 PU 401 Vehicle Speed Sensor Low Reference 45 YE 400 Vehicle Speed Sensor Signal 46-47 - - Not Used 48 L-BU/WH 1229 PC Solenoid Valve Low Control (Sol. A) 49 D-BU/WH 1231 A/T ISS Low Signal 50 YE 772 Transmission Range Switch Signal B 51 - - Not Used 52 WH 776 Transmission Range Switch Signal P 53-56 - - Not Used

Engine Controls Connector End Views

Accelerator Pedal Position (APP) Sensor Connector End Connector Part Information 15326830 6-Way F GT 150 Series (BK) Pin Wire Color Circuit No. Function A PU 1272 Low Reference B L-BU 1162 APP Sensor 2 Signal C TN 1274 5-Volt Reference D BN 1271 Low Reference E D-BU 1161 APP Sensor 1 Signal F WH/BK 1164 5-Volt Reference

Crankshaft Position (CKP) Sensor Connector End Connector Part Information 15449028 2-Way F GT 150 Series, Sealed (BK) Pin Wire Color Circuit No. Function A PU 574 Low Reference B YE 573 CKP Sensor Signal

Engine Coolant Temperature (ECT) Sensor Connector End Connector Part Information 15449028 2-Way F GT 150 Series, Sealed (BK) Pin Wire Color Circuit No. Function A TN 2761 Low Reference B YE 410 ECT Sensor Signal

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

Fuel Injector 1 Connector End Connector Part Information 15326180 2-Way F Micro-Pack 64 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK 139 Ignition 1 Voltage B BK 1744 Fuel Injector 1 Control

Fuel Injector 2 Connector End Connector Part Information 15326180 2-Way F Micro-Pack 64 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK 139 Ignition 1 Voltage B L-GN/BK 1745 Fuel Injector 2 Control

Fuel Injector 3 Connector End Connector Part Information 15326180 2-Way F Micro-Pack 64 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK 139 Ignition 1 Voltage B PK/BK 1746 Fuel Injector 3 Control

Fuel Injector 4 Connector End Connector Part Information 15326180 2-Way F Micro-Pack 64 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK 139 Ignition 1 Voltage B L-BU/BK 844 Fuel Injector 4 Control

Fuel Pump and Sender Assembly Connector End Connector Part Information 22666266 4-Way F (GY) Pin Wire Color Circuit No. Function 1 GY 120 Fuel Pump Supply Voltage 2 PU 1589 Fuel Level Sensor Signal 3 BK/WH 651 Low Reference 4 BK 1250 Ground

Fuel Tank Pressure (FTP) Sensor Connector End Connector Part Information 12059595 3-Way F Metri-Pack 150 Series, Sealed (BK) Pin Wire Color Circuit No. Function A OG/BK 469 Low Reference B D-GN 890 Fuel Tank Pressure Sensor Signal C GY 705 5-Volt Reference

Heated Oxygen Sensor (HO2S) Sensor 1 Connector End Connector Part Information 12160482 4-Way F Metri-Pack 150 Series, Sealed (BK) Pin Wire Color Circuit No. Function A TN/WH 3111 HO2S Low Signal B PU/WH 3110 HO2S High Signal C GY/WH 3113 HO2S Heater Low Control D PK/BK 5291 Ignition 3 Voltage

Heated Oxygen Sensor (HO2S) Sensor 2 Connector End Connector Part Information 12160825 4-Way M Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A TN/WH 3121 HO2S Low Signal B PU 3120 HO2S High Signal C GY/WH 3122 HO2S Heater Low Control D PK/BK 5291 Ignition 3 Voltage

Ignition Control Module (ICM) Connector End Connector Part Information 15464996 9-Way F GT 150 Series (BK) Pin Wire Color Circuit No. Function A PK 239 Ignition 1 Voltage B WH 423 IC Timing Control A C-D - - Not Used E BK 450 Ground F BN/WH 633 Camshaft Position Signal G OG 406 IC Timing Control B H-J - - Not Used

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

Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Connector End Connector Part Information 15326822 5-Way F GT 150 SLD 4.0 (BK) Pin Wire Color Circuit No. Function A YE 492 MAF Sensor Signal B BK/WH 451 Ground C PK/BK 5291 Engine Main Relay Fused Control 2 D TN/BK 2760 Low Reference E TN 472 IAT Sensor Signal

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

Throttle Actuator Control (TAC) Module Connector End Connector Part Information 15326835 8-Way F GT 150 SLD 4.0 (BK) Pin Wire Color Circuit No. Function A D-GN 485 TP Sensor 1 Signal B TN/WH 1704 Low Reference C GY 2701 5-Volt Reference D PU 486 TP Sensor 2 Signal E BN 582 TAC Motor Control - 2 F YE 581 TAC Motor Control - 1 G TN 2752 Low Reference H L-BU/BK 1688 5-Volt Reference

Removal Procedure

1. Using a scan tool, retrieve the percentage of remaining engine oil. Record the remaining engine oil life.
2. Record the preset radio stations.
3. Turn the ignition OFF.
4. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
5. Disconnect the PCM harness connectors.
6. Release the retaining tab located in the battery box lower half using a small screwdriver or other suitable tool.
7. Remove the PCM by lifting upward after releasing the tab.

Installation Procedure

1. Slide the PCM into the PCM bracket on the front of the battery box.
2. Push down on the PCM until the retaining tab snaps into place.
3. Connect the PCM harness connectors.
4. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical. Tighten: Tighten the battery terminal bolts to 17 N.m (13 lb ft).
5. Perform the crankshaft relearn procedure. Refer to «DTC P0315»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-controls-diagnosis-dtc-p0140-to-dtc-p0496-22l-l61) .
6. Verify no DTCs exist.
7. Reset the clock and preset radio stations.

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/malibu/vi-2003-2006/remont/oem-general-information/#vehicle-dtc-information__diagnostic-trouble-code-dtc-list) in Vehicle DTC Information for the applicable DTC that set.
3. Select the crankshaft position (CKP) variation learn procedure with a scan tool.
4. The scan tool instructs you to perform the following: Accelerate to wide open throttle (WOT). Release the throttle when the fuel cutoff occurs. Observe the fuel cutoff for the applicable engine. The 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 air conditioning (A/C) OFF. The 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: CKP sensors activity-If there is a CKP sensor condition, refer to the applicable DTC that set. Camshaft position (CMP) signal activity-If there is a CMP signal condition, refer to the applicable DTC that set. 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. Enable the CKP system variation learn procedure with the scan tool and perform the following: Accelerate to WOT. Release when 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/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-controls-diagnosis-dtc-p0140-to-dtc-p0496-22l-l61) . If any other DTCs set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/malibu/vi-2003-2006/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: Engine replacement PCM replacement A harmonic balancer replacement Crankshaft replacement CKP sensor replacement Any engine repairs which disturb the crankshaft to CKP sensor relationship

1. Turn the ignition OFF.
2. Disconnect the ECT sensor harness connector.
3. Remove the ECT (1).

1. Apply the thread sealant GM P/N 21485227, LOCTITE 242® Threadlocker or equivalent to the sensor threads.
2. Install the ECT sensor (1). Tighten: Tighten the ECT sensor to 20 N.m (15 lb ft).
3. Connect the ECT sensor harness connector. Push in the connector until a click is heard, then pull back to confirm a positive engagement.
4. Fill the engine coolant to the proper level.

1. Disconnect the mass air flow (MAF) sensor electrical connector.
2. Remove the MAF sensor screws.
3. Remove the MAF sensor from the air cleaner cover.

1. Install the MAF sensor to the air cleaner cover. Tighten: Tighten the screws to 0.6 N.m (5 lb in).
2. Connect the MAF sensor electrical connector.
3. Start and idle the engine.
4. Inspect the air intake duct for leaks.

1. Turn the ignition OFF.
2. Remove the air cleaner outlet resonator. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
3. Remove the throttle body. Refer to «Throttle Body Assembly Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
4. Disconnect the manifold absolute pressure (MAP) sensor harness connector.
5. Remove the MAP sensor and the MAP sensor port seal if it is still retained in the intake manifold

1. Install the MAP sensor with the port seal into the intake manifold
2. Connect the MAP sensor harness connector. Push in the connector until a click is heard and pull back to confirm a positive engagement.
3. Install the throttle body. Refer to «Throttle Body Assembly Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
4. Install the air cleaner outlet resonator. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

1. Remove the exhaust manifold heat shield. Refer to «Exhaust Manifold Replacement»(/chevrolet/malibu/vi-2003-2006/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
2. Disconnect the O2S harness connector.
3. Remove the O2S.

1. Coat the threads of the O2S with anti-seize compound, if necessary.
2. Install the O2S. Tighten: Tighten the O2S to 30 N.m (22 lb ft).
3. Connect the O2S harness connector.
4. Install the exhaust manifold heat shield. Refer to «Exhaust Manifold Replacement»(/chevrolet/malibu/vi-2003-2006/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.

Tools Required

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

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Note the routing of the heated oxygen sensor (HO2S) electrical harness (2).
3. Disconnect the HO2S electrical connector in the engine compartment (1).
4. Using the J 39194 carefully remove the HO2S.
5. Lower the HO2S electrical harness away from the underbody (1).

1. If reinstalling the old HO2S, coat the threads with anti-seize compound GM P/N 12377953 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 (1).
5. Connect the HO2S electrical connector (1).
6. Lower the vehicle.

1. Disconnect the accelerator pedal position sensor electrical connector.
2. Remove the accelerator mounting bolts (1) from the accelerator bracket.
3. Remove the accelerator assembly (2) from the vehicle.

1. Install the accelerator assembly (2) to the vehicle.
2. Install the accelerator mounting bolts (1) to the accelerator bracket. Tighten: Tighten the accelerator pedal nuts to 10 N.m (89 lb in).
3. Connect the accelerator pedal position sensor electrical connector.
4. Confirm that the accelerator sensor connector locking clip is fully secured.
5. Verify the operation of the accelerator pedal.

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 resonator. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
2. Disconnect the throttle body harness connector.
3. Remove the throttle body attaching bolts.
4. Remove the throttle body from the intake manifold.

1. Inspect the throttle body gasket and replace if necessary.
2. Install the throttle body to the intake manifold.
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 harness connector.
5. Install the air cleaner resonator. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

Fuel Pressure Relief Procedure

1. Loosen the fuel filler cap in order to relieve the tank pressure. Do not tighten at this time.
2. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Disconnect the fuel pump electrical connector.
4. Lower the vehicle.
5. Start and run the engine until the fuel supply remaining in the fuel pipes is consumed. Engage the starter for 3.0 seconds in order to assure relief of any remaining pressure.
6. Raise the vehicle.
7. Connect the fuel pump electrical connector.
8. Lower the vehicle.
9. Disconnect the negative battery 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/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.

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

1. Install the J 34730-1A to the fuel pressure service connection, located on the fuel rail. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
2. Turn ON the ignition.
3. Place the bleed hose of the fuel pressure gage into an approved gasoline container.
4. Open the bleed valve on the fuel pressure gage in order to bleed the air from the fuel pressure gage.
5. Command the fuel pump ON with a scan tool.
6. Close the bleed valve on the fuel pressure gage.
7. Inspect for fuel leaks.

1. Place the fuel pressure gage bleed hose into an approved container and open the bleed valve in order to bleed OFF fuel system pressure.
2. Place a shop towel under the fuel pressure gage in order to catch any remaining fuel spillage.
3. Remove the fuel pressure gage from the fuel pressure connection.
4. Drain any fuel remaining in the fuel pressure gage into an approved container.
5. Inspect for 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.
6. Install the cap on the fuel pressure connection.

J 37088-A Fuel Line Disconnect Tool Set

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-pressure-relief-procedure) .
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. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-pressure-relief-procedure) .
2. Blow dirt out of the fitting using compressed air.
3. Squeeze the plastic tabs of the male end connector.
4. Pull the connection apart.
5. Wipe off the male pipe end using a clean shop towel.
6. Inspect both ends of the fitting for dirt and burrs.
7. 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 quick-connect fitting together in order to cause the retaining tabs to snap into place.
3. Pull on both sides of the quick connect fitting in order to make sure the connection is secure.

Fuel Tank Draining Procedure

Tools Required

1. J 36850 Transjel Lubricant
2. J 42960-2 Fuel Flapper Door Holder. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
3. J 45004 Fuel Tank Drain Hose. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

1. Remove the fuel filler cap.
2. Install the J 42960-2 into the fuel fill pipe in order to hold the door open. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
3. Insert the J 45004 into the fuel tank until the hose reaches the bottom of the fuel tank. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
4. Use an hand or air operated pump device in order to drain as much fuel through the fuel fill pipe as possible.

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-pressure-relief-procedure) .
2. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-tank-draining-procedure) .
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Disconnect the fuel pump module harness electrical connector from the vehicle underbody wiring harness.
5. Disconnect the evaporative emissions (EVAP) vent valve solenoid harness electrical connector from the vehicle underbody wiring harness.
6. If applicable, disengage the antilock brake system (ABS) wiring harness from the retainer on the side of the EVAP canister.
7. Disconnect the fuel feed and purge lines at the fuel and brake line bundle on the right side of the vehicle.
8. Cap or plug the fuel tank feed and vapor return pipes to prevent fuel loss and/or contamination.
9. Loosen the fuel filler pipe jumper hose clamp at the fuel tank (1).
10. Disconnect the fuel filler pipe jumper hose from the fuel tank.
11. Disconnect the vapor recirculation line that runs parallel to the fuel filler pipe jumper hose.
12. Release the exhaust pipe insulators from the underbody hangers.
13. Release the muffler insulator from the underbody hanger and slowly lower the exhaust to rest on a tall jackstand. If this is not possible, remove the rear half of the exhaust system at the take down flange.
14. Have an assistant support the fuel tank during fuel tank strap removal, and during tank removal. Or use an appropriate jack to support the fuel tank during removal
15. Remove front LH fuel tank strap bolts.
16. Remove the RH tank strap bolts.
17. In order to clear the exhaust pipe, slowly lower the RH side of the fuel tank.
18. Once the tank is clear of the RH frame rail, remove the fuel tank down and forward toward the RH side of the vehicle.
19. If only the fuel tank is to be replaced, remove the fuel pump module assembly from the fuel tank. Refer to «Fuel Sender Assembly Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Sender Assembly Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

1. If fuel tank replacement was necessary, install the fuel pump module assembly to the fuel tank. Refer to «Fuel Sender Assembly Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Sender Assembly Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
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, the EVAP vapor pipe, and the fuel pump module electrical harness over the exhaust system.
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 20 N.m (15 lb ft).
8. Raise the exhaust into position and install the muffler insulator 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 pipe jumper hose to the fuel tank.
12. Tighten the fuel filler pipe jumper hose clamp (1) at the fuel tank. Tighten: Tighten the clamp to 4 N.m (35 lb in).
13. Connect vapor recirculation line that runs parallel to the fuel filler pipe jumper hose.
14. Remove the caps or plugs from the fuel tank feed and vapor return pipes.
15. Connect the fuel feed and vapor purge lines to the fuel and brake line bundle on the right side of the vehicle.
16. Connect the fuel sender electrical connector to the underbody harness and connect the EVAP purge valve electrical connector to the underbody harness.
17. Attach the ABS harness (if applicable) to the retainer on the side of the EVAP canister.
18. Lower the vehicle.
19. Refill the fuel tank.
20. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
21. 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. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-pressure-relief-procedure) .
2. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-tank-draining-procedure) .
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Disconnect the fuel pump module harness electrical connector from the vehicle underbody wiring harness.
5. Disconnect the evaporative emissions (EVAP) vent valve solenoid harness electrical connector from the vehicle underbody wiring harness.
6. If applicable, disengage the antilock brake system (ABS) wiring harness from the retainer on the side of the EVAP canister.
7. Disconnect the fuel feed and purge lines at the fuel and brake line bundle on the right side of the vehicle.
8. Cap or plug the fuel tank feed and vapor return pipes to prevent fuel loss and/or contamination.
9. Loosen the fuel filler pipe jumper hose clamp at the fuel tank (1).
10. Disconnect the fuel filler pipe jumper hose from the fuel tank.
11. Disconnect the vapor recirculation line that runs parallel to the fuel filler pipe jumper hose.
12. Release the exhaust pipe insulators from the underbody hangers.
13. Release the muffler insulator from the underbody hanger and slowly lower the exhaust to rest on a tall jackstand. If this is not possible, remove the rear half of the exhaust system at the take down flange.
14. Have an assistant support the fuel tank during fuel tank strap removal, and during tank removal. Or use an appropriate jack to support the fuel tank during removal
15. Remove front LH fuel tank strap bolts.
16. Remove the RH tank strap bolts.
17. In order to clear the exhaust pipe, slowly lower the RH side of the fuel tank.
18. Once the tank is clear of the RH frame rail, remove the fuel tank down and forward toward the RH side of the vehicle.
19. If only the fuel tank is to be replaced, remove the fuel pump module assembly from the fuel tank. Refer to «Fuel Sender Assembly Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Sender Assembly Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

1. If fuel tank replacement was necessary, install the fuel pump module assembly to the fuel tank. Refer to «Fuel Sender Assembly Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Sender Assembly Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
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, the EVAP vapor pipe, and the fuel pump module electrical harness over the exhaust system.
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 20 N.m (15 lb ft).
8. Raise the exhaust into position and install the muffler insulator 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 pipe jumper hose to the fuel tank.
12. Tighten the fuel filler pipe jumper hose clamp (1) at the fuel tank. Tighten: Tighten the clamp to 4 N.m (35 lb in).
13. Connect vapor recirculation line that runs parallel to the fuel filler pipe jumper hose.
14. Remove the caps or plugs from the fuel tank feed and vapor return pipes.
15. Connect the fuel feed and vapor purge lines to the fuel and brake line bundle on the right side of the vehicle.
16. Connect the fuel sender electrical connector to the underbody harness and connect the EVAP purge valve electrical connector to the underbody harness.
17. Attach the ABS harness (if applicable) to the retainer on the side of the EVAP canister.
18. Lower the vehicle.
19. Refill the fuel tank.
20. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
21. 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. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Relieve the system fuel pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-pressure-relief-procedure) .
3. Drain fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-tank-draining-procedure) .
4. Remove the fuel tank. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
5. Remove the electrical connector from the fuel tank pressure (FTP) sensor.
6. Remove the FTP sensor from modular fuel sender.

1. Install the new FTP sensor to modular fuel sender.
2. Install the electrical connector to FTP sensor.
3. Install the fuel tank. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
4. Refill the tank.
5. Install the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.

1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Relieve the system fuel pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-pressure-relief-procedure) .
3. Drain fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-tank-draining-procedure) .
4. Remove the fuel tank. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
5. Remove the electrical connector from the fuel tank pressure sensor.
6. Remove the fuel tank pressure sensor from modular fuel sender.

1. Install the new fuel tank pressure sensor to modular fuel sender.
2. Install the electrical connector to fuel tank pressure sensor.
3. Install the fuel tank. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
4. Refill tank.
5. Install the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.

1. Remove the fuel pump module assembly. Refer to «Fuel Sender Assembly Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Sender Assembly Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
2. Release the fuel level sensor wiring harness from the molded-in tab on the pump module bowl.
3. Disconnect the fuel level sensor electrical connector from the pump module cover.
4. Depress the retaining tab 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 on the sensor into the slot on the pump module bowl.
3. Connect the fuel level sensor electrical connector to the pump module cover.
4. Install the fuel level sensor wiring harness to the molded-in tab on the pump module bowl.
5. Install the fuel pump module assembly. Refer to «Fuel Sender Assembly Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Sender Assembly Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

1. Remove the fuel pump module assembly. Refer to «Fuel Sender Assembly Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Sender Assembly Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
2. Release the fuel level sensor wiring harness from the molded-in tab on the pump module bowl.
3. Disconnect the fuel level sensor electrical connector from the pump module cover.
4. Depress the retaining tab 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 on the sensor into the slot on the pump module bowl.
3. Connect the fuel level sensor electrical connector to the pump module cover.
4. Install the fuel level sensor wiring harness to the molded-in tab on the pump module bowl.
5. Install the fuel pump module assembly. Refer to «Fuel Sender Assembly Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Sender Assembly Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

J 45722 Fuel Sender Lock Ring Wrench. See Special Tools and Equipment .

1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Relieve the system fuel pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-pressure-relief-procedure) .
3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-tank-draining-procedure) .
4. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
5. Remove the fuel tank. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
6. Disconnect the electrical and ventilation connections on the modular fuel sender assembly cover.
7. While having an assistant hold the fuel tank, use J 45722 to turn the modular fuel sender assembly lock ring counter-clockwise until the ring is released from the fuel tank. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
8. Raise the fuel sender assembly out of the tank far enough to access the ventilation harness connection on the underside of the module cover.
9. Disconnect the ventilation harness quick connect before attempting to fully remove the modular fuel sender assembly.

1. Install a new O-ring on the modular fuel sender to tank.
2. Connect the ventilation harness inside the fuel tank to the bottom of the modular fuel sender cover.
3. Slowly apply pressure to the top of the spring loaded sender cover until the sender aligns flush with the surface of the tank.
4. Align the locking ring with the matching features on the fuel tank and install the J 45722 . See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
5. Turn the lock ring until the ring seats on the second detent.
6. Connect the electrical and ventilation connections to the modular fuel sender assembly cover.
7. Install the fuel tank. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
8. Lower the vehicle.
9. Refill the tank.
10. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
11. Inspect for fuel leaks through the following steps: Turn the ignition to the ON position for two seconds Turn the ignition to the OFF position for ten seconds. Turn the ignition to the ON position Check for fuel leaks.

J 45722 Fuel Sender Lock Ring Wrench. See Special Tools and Equipment .

1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Relieve the system fuel pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-pressure-relief-procedure) .
3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-tank-draining-procedure) .
4. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
5. Remove the fuel tank. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
6. Disconnect the electrical and ventilation connections on the modular fuel sender assembly cover.
7. While having an assistant hold the fuel tank, use J 45722 to turn the modular fuel sender assembly lock ring counter-clockwise until the ring is released from the fuel tank. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
8. Raise the fuel sender assembly out of the tank far enough to access the ventilation harness connection on the underside of the module cover.
9. Disconnect the ventilation harness quick connect before attempting to fully remove the modular fuel sender assembly.

1. Install a new O-ring on the modular fuel sender to tank.
2. Connect the ventilation harness inside the fuel tank to the bottom of the modular fuel sender cover.
3. Align the cover "paddle" or anti-rotation feature with the corresponding feature in the top of the fuel tank.
4. Slowly apply pressure to the top of the spring loaded sender cover until the sender aligns flush with the surface of the tank.
5. Align the locking ring with the matching features on the fuel tank and install the J 45722 . See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
6. Turn the lock ring until the ring seats on the second detent.
7. Connect the electrical and ventilation connections to the modular fuel sender assembly cover.
8. Install the fuel tank. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
9. Lower the vehicle.
10. Refill the tank.
11. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
12. Inspect for fuel leaks through the following steps: Turn the ignition to the ON position for two seconds Turn the ignition to the OFF position for ten seconds. Turn the ignition to the ON position Check for fuel leaks.

1. Remove the fuel fill cap.
2. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-tank-draining-procedure) .
3. Remove the fuel filler pipe bolt from the fuel fill pocket.
4. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
5. Remove the fuel filler pipe attaching screw from the underbody.
6. Loosen the fuel filler hose clamp at the fuel tank.
7. Remove the fuel filler hose from the fuel tank.
8. Remove the fuel filler pipe assembly.

1. Install the fuel filler pipe upper end to the fuel filler pocket and position fuel filler pipe.
2. Install the fuel filler pipe attaching screw to the underbody. Tighten: Tighten the fuel filler pipe attaching screw to 10 N.m (89 lb in).
3. Install the fuel filler jumper hose to the fuel tank.
4. Position the fuel filler hose clamp at the fuel tank and fuel fill tube. Tighten: Tighten the fuel tank filler hose clamps to 4 N.m (35 lb in).
5. Lower the vehicle.
6. Install the bolt in the fuel filler pocket. Tighten: Tighten the fuel tank filler pocket bolt to 1.5 N.m (13 lb in).
7. Install the fuel filler cap.

Note. Cap the fittings and plug the holes when servicing the fuel system in order to prevent dirt and other contaminants from entering the open pipes and passages.

1. Remove the fuel fill cap.
2. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-tank-draining-procedure) .
3. Remove the fuel filler pipe bolt from the fuel fill pocket.
4. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
5. Remove the fuel filler pipe attaching screw from the underbody.
6. Loosen the fuel filler hose clamp at the fuel tank.
7. Remove the fuel filler hose from the fuel tank.
8. Remove the fuel filler pipe assembly.

1. Install the fuel filler pipe upper end to the fuel filler pocket and position fuel filler pipe.
2. Install the fuel filler pipe attaching screw to the underbody. Tighten: Tighten the fuel filler pipe attaching screw to 10 N.m (89 lb in).
3. Install the fuel filler jumper hose to the fuel tank.
4. Position the fuel filler hose clamp at the fuel tank and fuel fill tube. Tighten: Tighten the fuel tank filler hose clamps to 4 N.m (35 lb in).
5. Lower the vehicle.
6. Install the bolt in the fuel filler pocket. Tighten: Tighten the fuel tank filler pocket bolt to 1.5 N.m (13 lb in).
7. Install the fuel filler cap.

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-pressure-relief-procedure) .
2. Disconnect the engine fuel feed pipe from the chassis fuel flex hose. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
3. Using a backup wrench on the fuel rail, disconnect the fuel feed pipe at the fuel rail.
4. Remove the fuel feed pipe fastener located at the top of the exhaust manifold heat shield.
5. 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 10 N.m (89 lb in).
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/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
4. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
5. Inspect for leaks using the following procedure: Turn ON the ignition, with the engine OFF for 2 seconds. Inspect for fuel leaks. Turn OFF the ignition for 10 seconds. Turn ON the ignition.

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-pressure-relief-procedure) .
2. Remove the pipe retaining clip from the fuel feed pipe (1).
3. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Disconnect the fuel feed pipe from the engine fuel rail. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
5. Cap or plug the fuel pipe and the engine fuel rail to prevent contamination.
6. Remove the rear brake pipe bracket retaining nuts and release the brackets from the body studs.
7. Release the pipe retainers (1) from the vehicle underbody.
8. Remove the fuel feed pipe from the pipe retainers.
9. Lower the rear of the pipe while moving the pipe rearward slightly, then lower the front of the pipe.
10. 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. Connect the fuel feed pipe and vapor return pipe to the lines at the fuel tank.
7. Lower the vehicle.
8. Remove the caps or plugs from the fuel pipe and the engine fuel rail.
9. Connect the fuel feed pipe to the engine fuel rail. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
10. Install the pipe retaining clip (1) to the fuel feed pipe.
11. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
12. 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 (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) and «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
2. Remove the fuel pump module assembly. Refer to «Fuel Sender Assembly Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) or «Fuel Sender Assembly Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
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. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
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. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
10. Install the fuel pump module assembly. Refer to «Fuel Sender Assembly Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) or «Fuel Sender Assembly Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
11. Install the fuel tank. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) or «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-pressure-relief-procedure) .
2. Remove the air cleaner outlet resonator. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
3. Disconnect the vacuum pipe from the fuel pressure regulator.
4. Remove the engine fuel supply and return pipes. Refer to «Fuel Hose/Pipes Replacement - Engine Compartment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
5. Disconnect the fuel injector harness connectors.
6. Remove the fuel rail attaching studs.
7. 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.
8. Remove the fuel injectors. Refer to «Fuel Injector Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

1. Install the fuel injectors. Refer to «Fuel Injector Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
2. 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.
3. Install the fuel rail attaching studs. Tighten: Tighten the fuel rail studs to 10 N.m (89 lb in).
4. Connect the fuel injector harness connectors. Pull back to insure the connectors are locked in place.
5. Install the fuel supply and return pipes. Refer to «Fuel Hose/Pipes Replacement - Engine Compartment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
6. Connect the vacuum pipe to the fuel pressure regulator.
7. Install the air cleaner outlet resonator. Refer to «Air Cleaner Outlet Resonator Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
8. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
9. 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.

Fuel Injector Cleaning Procedure

Tools Required

1. J 37287 Fuel Line Shut-Off Adapters. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
2. J 35800-A Fuel Injector Cleaner
3. J 42873-1 3/8 Fuel Line Shut-Off Valve. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
4. J 42873-2 5/16 Return Pipe Shut-Off Valve. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
5. J 42964-1 3/8 Fuel Pipe Shut-Off Valve. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
6. J 42964-2 5/16 Fuel Pipe Shut-Off Valve. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

Note. GM Top-Engine Cleaner is the only injector cleaning agent recommended. Do not use other cleaning agents, as they may contain methanol which can damage fuel system components. Under NO circumstances should the top engine cleaner be added to the vehicles fuel tank, as it may damage the fuel pump and other system components. Do not exceed a 10 percent cleaning solution concentration. Higher concentrations may damage fuel system components. Testing has demonstrated that exceeding the 10 percent cleaning solution concentration does not improve the effectiveness of this procedure.

1. Obtain J 35800-A (2).
2. For US dealers, empty 2 pre-measured GM Top-Engine Cleaner containers, 24 ml (0.812 oz) each, GM P/N 12346535, into the J 35800-A .
3. For Canadian dealers, measure and dispense 48 ml (1.62 oz) of Top-Engine Cleaner, Canadian P/N 992872, into the J 35800-A .
4. If you are using any other brand of tank you will need a total of 96 ml (3.24 oz) of Top-Engine Cleaner mixed with 864 ml (29.16 oz) of regular unleaded gasoline.
5. Fill the injector cleaning tank with regular unleaded gasoline. Be sure to follow all additional instructions provided with the tool.
6. Electrically disable the vehicle fuel pump by removing the fuel pump relay and disconnecting the oil pressure switch connector, if equipped.
7. Disconnect the fuel feed and return line, if equipped, at the fuel rail. Plug the fuel feed and return line, if equipped, coming off the fuel rail with J 37287 , or J 42964-1 and J 42964-2 or J 42873-1 and J 42873-2 as appropriate for the fuel system. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
8. Connect the J 35800-A to the vehicle fuel rail.
9. Pressurize the J 35800-A to 510 kPa (75 psi).
10. Start and idle the engine until it stalls due to lack of fuel. This should take approximately 15-20 minutes.
11. Disconnect J 35800-A from the fuel rail.
12. Reconnect the vehicle fuel pump relay and oil pressure switch connector, if equipped.
13. Remove J 37287 or J 42964-1 and J 42964-2 or J 42873-1 and J 42873-2 and reconnect the vehicle fuel feed and return lines. See «Special Tools and Equipment»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
14. Start and idle the vehicle for an additional 2 minutes to ensure residual injector cleaner is flushed from the fuel rail and fuel lines.
15. Repeat steps 1-5 of the Injector Balance Test, and record the fuel pressure drop from each injector.
16. Subtract the lowest fuel pressure drop from the highest fuel pressure drop. If the value is 15 kPa (2 psi) or less, no additional action is required. If the value is greater than 15 kPa (2 psi), replace the injector with the lowest fuel pressure drop.
17. Add one ounce of Port Fuel Injector Cleaner, GM P/N 12345104 (Canadian P/N 10953467), to the vehicle fuel tank for each gallon of gasoline estimated to be in the fuel tank. Instruct the customer to add the reminder of the bottle of Port Fuel Injector Cleaner to the vehicle fuel tank at the next fill-up.
18. Advise the customer to change brands of fuel and to add GM Port Fuel Injector Cleaner every 5 000 km (3,000 mi). GM Port Fuel Injector Cleaner contains the same additives that the fuel companies are removing from the fuel to reduce costs. Regular use of GM Port Fuel Injector Cleaner should keep the customer from having to repeat the injector cleaning procedure.
19. Road test the vehicle to verify that the customer concern has been corrected.

Note. Use care in removing the fuel injectors in order to prevent damage to the fuel injector electrical connector pins or the fuel injector nozzles. Do not immerse the fuel injector in any type of cleaner. The fuel injector is an electrical component and may be damaged by this cleaning method.

1. Remove the fuel rail. Refer to «Fuel Rail Assembly Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
2. Remove the fuel injector retaining clip (1).
3. Remove the fuel injector (3) from the fuel rail.
4. Remove the fuel injector upper O-ring (2).
5. Remove the fuel injector lower O-ring (4).

1. The fuel injector assembly (1) is stamped with a part number identification (2).
2. Lubricate the new injector O-rings (2, 4) with clean engine oil.
3. Install the fuel injector upper O-ring (2).
4. Install the fuel injector lower O-ring (4).
5. Install the fuel injector (3) to the fuel rail.
6. Install the fuel injector retaining clip (1).
7. Install the fuel rail. Refer to «Fuel Rail Assembly Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

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. If there is any loose carbon, replace the EVAP canister and any components necessary to remove the carbon particles.

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 the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Lower and support the vehicle exhaust system.
3. Loosen the fastener on the left-hand fuel tank strap - do not remove the fastener.
4. Support the fuel tank with a suitable jackstand.
5. Loosen and remove the front bolt in the right-hand fuel tank strap
6. Disconnect the fuel fill pipe at the fuel tank and disconnect the vapor line on the fuel fill pipe.
7. Lower the right side of the fuel tank far enough to access the EVAP canister vent valve.
8. Disconnect the EVAP canister vent valve hose.
9. Disconnect the EVAP canister electrical connector.
10. Using a small flat-blade screwdriver, push back the release tab on the EVAP canister vent valve mounting foot.
11. Slide the EVAP canister vent valve toward the rear of the vehicle and off of the mounting foot.

1. Slide the new EVAP canister vent valve onto the mounting foot on the fuel tank.
2. Slide the valve forward until it snaps into place on the mounting foot.
3. Connect the hose to the EVAP canister vent valve.
4. Connect the EVAP vent valve harness connector.
5. Raise the fuel tank back into position and install the fasteners. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) or «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
6. Reconnect the fuel fill pipe at the fuel tank and connect the vapor line on the fuel fill pipe.

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Lower the fuel tank enough on the RH side to access the purge valve. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) or «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) . It is not necessary to fully remove the fuel tank from the vehicle.
3. Disconnect the evaporative emission (EVAP) vent valve electrical connector.
4. Remove the vent hose.
5. Depress the locking tab on the EVAP vent valve mount and slide the valve rearward off of the fuel tank.

1. Install the EVAP canister vent valve on the mount on the fuel tank, push the valve forward until the locking tab engages. Tighten: Tighten the bolt to 10 N.m (89 lb in).
2. Connect the vent hose.
3. Connect the electrical connector.
4. Install the fuel tank Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) or «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
5. Lower the vehicle.

1. Remove the air cleaner intake duct assembly. Refer to «Air Cleaner Intake Duct Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
2. Disconnect the engine purge pipe from the evaporative emission (EVAP) canister purge valve.
3. Remove the engine purge pipe.

1. Connect the engine purge pipe (3) to the evaporative emission (EVAP) canister purge valve (2).
2. Install the air cleaner intake duct assembly. Refer to «Air Cleaner Intake Duct Replacement»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__fuel-pressure-relief-procedure) .
2. Remove the pipe retaining clip from the fuel feed pipe (1).
3. Disconnect the fuel feed pipe from the engine fuel rail. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
4. Cap or plug the fuel pipe and the engine fuel rail to prevent contamination.
5. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
6. Remove the rear brake pipe bracket retaining nuts and release the brackets from the body studs.
7. Release the pipe retainers (1) from the vehicle underbody.
8. Remove the fuel feed pipe from the pipe retainers.
9. Lower the rear of the pipe while moving the pipe rearward slightly, then lower the front of the pipe.
10. 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. Connect the fuel feed pipe and vapor return pipe to the lines at the fuel tank.
7. Lower the vehicle.
8. Remove the caps or plugs from the fuel pipe and the engine fuel rail.
9. Connect the fuel feed pipe to the engine fuel rail. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
10. Install the pipe retaining clip (1) to the fuel feed pipe.
11. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
12. 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. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the fuel tank from the vehicle. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) or «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
3. Disconnect the EVAP canister vent valve hose.
4. Disconnect the vapor line from the fuel tank to the EVAP canister.
5. Disconnect the purge line from the EVAP canister.
6. Remove the screw in the EVAP canister mounting pad on the fuel tank and slide the EVAP canister upward off of the mount.

1. Slide the new EVAP canister onto the mount on the fuel tank.
2. Install the screw into the EVAP canister mount to secure the canister to the fuel tank.
3. Connect purge line to the EVAP canister.
4. Connect the vapor line from the fuel tank to the EVAP canister.
5. Connect the EVAP canister vent valve hose to the vent valve.
6. Install the fuel tank back in the vehicle. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) or «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vi-2003-2006/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the fuel tank from the vehicle. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) or «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .
3. Disconnect the EVAP canister vent valve hose.
4. Disconnect the vapor line from the fuel tank to the EVAP canister.
5. Disconnect the purge line from the EVAP canister.
6. Remove the screw in the EVAP canister mounting pad on the fuel tank and slide the EVAP canister upward off of the mount.

1. Slide the new EVAP canister onto the mount on the fuel tank.
2. Install the screw into the EVAP canister mount to secure the canister to the fuel tank.
3. Connect purge line to the EVAP canister.
4. Connect the vapor line from the fuel tank to the EVAP canister.
5. Connect the EVAP canister vent valve hose to the vent valve.
6. Install the fuel tank back in the vehicle. Refer to «Fuel Tank Replacement (Malibu Sedan)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) or «Fuel Tank Replacement (Malibu MAXX)»(/chevrolet/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61) .

1. Turn the ignition OFF.
2. Disconnect the EI module harness connector.
3. Remove the ignition coil housing attachment bolts and remove the ignition coil housing. Ignition coil housing (1) Spark plug boot (2)

1. Apply the dielectric compound to the spark plug boots and make sure no corrosion is present.
2. Install the ignition coil housing to the cam cover and the attachment bolts.
3. Install the EI module and the attachment screws. Tighten: Tighten the ignition coil housing bolts to 10 N.m (89 lb in).
4. Connect the EI module harness connector. Push in the connector until a click is heard and pull back to confirm a positive engagement. Tighten: Tighten the EI module screws to 1.5 N.m (13 lb in).

1. Turn the ignition OFF.
2. Disconnect the electronic ignition (EI) module harness connector.
3. Remove the EI module attachment screws and the EI module.

1. Install the EI module and the attachment screws. Tighten: Tighten the EI module screws to 1.5 N.m (13 lb in).
2. Connect the module harness connector. Push in the connector until a click is heard, then pull back to confirm a positive engagement.

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/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__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/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__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/malibu/vi-2003-2006/remont/testing-diagnostics/#engine-control-system-introduction-22l-l61__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.

1. Turn the ignition OFF.
2. Disconnect the electronic ignition (EI) module harness connector.
3. Remove the ignition coil housing attachment bolts and remove the ignition coil housing.
4. Remove the spark plugs using a 5/8 inch spark plug socket.

1. Install the spark plugs. Tighten: Tighten the spark plugs to 20 N.m (15 lb ft). Specification: The spark plug gap is 1.1 mm (0.45 in).
2. Apply dielectric compound to the spark plug boots and make sure no corrosion is present.
3. Install the ignition coil housing to cam cover and attachment bolts. Tighten: Tighten the ignition coil housing bolts to 10 N.m (89 lb in).
4. Connect the EI module harness connector. Push in until a click is heard and pull back to confirm a positive engagement.

1. Record the preset radio stations.
2. Turn the ignition OFF.
3. Disconnect the negative battery cable. Engine Harness Connection (1). Battery Feed (2). Starter Motor (3). Starter Solenoid (4).
4. Raise the vehicle.
5. Remove the 2 starter solenoid harness connector attachment nuts.
6. Remove the lower starter assembly to the engine block bolt.
7. Remove the upper starter assembly to the engine block bolt.
8. Move the starter right to clear the engine block, then left to remove the starter from the flywheel housing.
9. Disconnect the CKP sensor harness connector.
10. Remove the CKP sensor attachment bolt and the CKP sensor.

1. Lubricate the CKP sensor O-ring with clean engine oil.
2. Install the CKP sensor in the engine block and attachment bolt. Tighten: Tighten the crankshaft position sensor bolt to 10 N.m (89 lb in).
3. Connect the CKP sensor harness connector. Push in the connector until a click is heard, then pull back to confirm a positive engagement.
4. Install the starter into the flywheel housing and align the bolt holes.
5. Install the upper and lower starter assembly to the engine block bolts. Tighten: Tighten the starter-to-engine bolts to 40 N.m (30 lb ft).
6. Install the two starter solenoid harness connections and attachment nuts. Tighten: Tighten the starter solenoid harness nuts (large) to 9 N.m (80 lb in). Tighten the starter solenoid harness nuts (small) to 3 N.m (27 lb in).
7. Lower the vehicle.
8. Connect the negative battery cable. Tighten: Tighten the battery terminal bolts to 17 N.m (13 lb ft).
9. Reset the clock to preset the radio stations.

1. Record the preset radio station.
2. Turn the ignition OFF.
3. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/malibu/vi-2003-2006/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
4. Remove the knock sensor (KS) harness connector.
5. Remove the KS from the retaining clip by inserting a flat-bladed screwdriver between the connector and the clip while sliding the connector upward.
6. Remove the KS.

1. Insert the KS pigtail connector with the retaining clip into the intake manifold hole or slide the KS pigtail connector over the retaining clip from the top.
2. Connect the KS harness connector. Push in the connector until a click is heard, then pull back to confirm a positive engagement.
3. Install the KS at the 9 o'clock position and the attachment bolt. Tighten: Tighten the knock sensor-to-engine block bolt to 25 N.m (18 lb ft).
4. Connect the negative battery cable. Tighten: Tighten the battery terminal bolts to 17 N.m (13 lb ft).
5. Reset the clock and preset radio stations.

1. Disconnect the manifold absolute pressure (MAP) sensor harness connector.
2. Remove the upper air cleaner cover screws.
3. Remove the upper air cleaner cover.
4. Remove the air cleaner filter from the lower air cleaner housing.
5. Inspect the air cleaner filter for dust, dirt and water contamination.
6. Replace as necessary. Refer to «Scheduled Maintenance»(/chevrolet/malibu/vi-2003-2006/remont/lubrication-system/#maintenance-and-lubrication__scheduled-maintenance) in Maintenance and Lubrication.

1. Install the air cleaner filter into the lower air cleaner housing.
2. Install the upper air cleaner cover to the lower air cleaner housing.
3. Secure the air cleaner housing cover. Tighten: Tighten the air cleaner cover screws to 5 N.m (44 lb in).
4. Connect the mass air flow (MAF) sensor harness connector.

1. Loosen the outlet duct clamp at the air cleaner assembly.
2. Remove the air cleaner assembly attachment nut.
3. Remove the air cleaner.

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

1. Loosen the 2 intake air duct clamps from the air cleaner cover and the throttle body.
2. Disconnect the positive crankcase ventilation clean air tube from the intake duct.
3. Separate the air intake duct from the air cleaner cover and the throttle body.

1. Install the air intake duct to the air cleaner cover and throttle body.
2. Reconnect the positive crankcase ventilation clean air tube to the air intake duct.
3. Tighten the air intake duct clamps. Tighten: Tighten the intake air duct clamps to 2 N.m (18 lb in).

1. Loosen the 2 intake air duct clamps from the air cleaner cover and the throttle body.
2. Disconnect the positive crankcase ventilation clean air tube from the intake duct.
3. Separate the air intake duct from the air cleaner cover and the throttle body.

1. Install the air intake duct to the air cleaner cover and throttle body.
2. Reconnect the positive crankcase ventilation clean air tube to the air intake duct.
3. Tighten the air intake duct clamps. Tighten: Tighten the intake air duct clamps to 2 N.m (18 lb in).

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 84

Scheme 85

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.

Fuel System Overview

The fuel system is a returnless on-demand design. The fuel pressure regulator is a part of the fuel sender assembly, eliminating the need for a return pipe from the engine. A returnless fuel system reduces the internal temperature of the fuel tank by not returning hot fuel from the engine to the fuel tank. Reducing the internal temperature of the fuel tank results in lower evaporative emissions.

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 contained in the fuel sender assembly 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 cracking 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 frame. The fuel tank is molded from high-density polyethylene.

Scheme 86

The fuel fill pipe (2) 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.

Scheme 87

The fuel sender assembly consists of the following major components

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

Scheme 88

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 control module sends the fuel level information via the Class 2 circuit to the instrument panel cluster (IPC). This information is used for the IPC fuel gage and the low fuel warning indicator, if applicable. The control module 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 contained in the fuel sender assembly inside the fuel tank. 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.

Scheme 89

The fuel pressure regulator (2) is contained in the left 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. A software bias compensates the injector on-time because the fuel pressure regulator is not referenced to the manifold vacuum. The fuel pressure regulator keeps fuel available to the injectors at a regulated pressure.

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. There are 2 sizes of nylon pipes used

1. 9.53 mm (3/8 in) ID for the fuel feed
2. 12.7 mm (1/2 in) ID for the vent

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 90

The fuel rail assembly attaches to the engine intake manifold. The fuel rail assembly performs the following functions

1. Positions the injectors (5) in the intake manifold
2. Distributes fuel evenly to the injectors
3. Integrates the fuel pulse dampener (2) into the fuel metering system

Scheme 91

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 ohms, 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 (2). 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. The fuel pressure regulator compensates for engine load by increasing fuel pressure as the engine vacuum drops.

Scheme 92

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 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 ECT, MAP, and 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 each different 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 TP, the ECT, the 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 TP, and the 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 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 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 key OFF. Because of this, it may be normal for the control module to remain active for up to 40 minutes after the engine is turned OFF. This is important to remember when performing a parasitic draw test on vehicles equipped with EONV.

The EONV diagnostic 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 start to drop. The EONV diagnostic relies on this temperature change and it's corresponding pressure change to determine if an EVAP system leak is present.

The EONV diagnostic is designed to detect leaks as small as 0.51 mm (0.02 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 (0.02 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 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

If equipped, 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 evaporative emission (EVAP) purge solenoid valve controls the flow of vapors from the EVAP system to the intake manifold. The 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 evaporative emission (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 evaporative emission (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 Description

The electronic ignition (EI) system produces and controls a high energy secondary spark. This spark is used to ignite the compressed air/fuel mixture at precisely the correct time. This provides optimal performance, fuel economy, and control of exhaust emissions. This ignition system uses one coil for each pair of cylinders. Each pair of cylinders that are at top dead center (TDC) at the same time are known as companion cylinders. The cylinder that is at TDC of its compression stroke is called the event cylinder. The cylinder that is at TDC of its exhaust stroke is called the waste cylinder. When the ignition coil is triggered, both companion cylinder spark plugs fire at the same time, completing a series circuit. Because the lower pressure inside the waste cylinder offers very little resistance, the event cylinder uses most of the available voltage to produce a very high energy spark. This is known as waste spark ignition. The ignition coils and ignition control module (ICM) are contained within one assembly. The ignition coil/ICM assembly is mounted in the center of the engine camshaft cover, with short boots connecting the ignition coils to the spark plugs. The ignition coil driver modules within the ICM are commanded ON/OFF by the powertrain control module (PCM). The EI system consists of the following components

Crankshaft Reluctor Wheel

The crankshaft reluctor wheel is part of the crankshaft. The reluctor wheel has seven machined notches, six of which are equally spaced 60 degrees apart. The seventh notch is spaced 10 degrees after one of the 60-degree notches. The 10-degree notch is used to synchronize the engine position, while the other notches are used to provide cylinder location during a revolution.

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 different amplitude and frequency. The frequency depends on the velocity of the crankshaft. The AC voltage output depends on the crankshaft position and the battery voltage. The CKP sensor works in conjunction with a 7X reluctor wheel attached to the crankshaft. The CKP sensor produces 7 pulses for each revolution of the crankshaft. The pulse from the 10-degree notch is known as the sync pulse. The sync pulse is used to synchronize the coil firing sequence with the crankshaft position. The CKP sensor is used for ignition timing, the fuel injector timing, misfire diagnostics and tachometer display. The CKP sensor is connected to the ECM by a signal circuit and a low reference circuit.

Scheme 93

The powertrain control module (PCM) supplies a signal on each of the ignition control (IC) timing control circuits to the ignition control module (ICM). The ICM fires the correct ignition coil at the correct time based on the signals. The ICM detects if cylinder 1 or cylinder 3 is on the compression stroke by sensing the secondary voltage and polarity of each side of the ignition coil. The ICM detects this voltage with sensing circuitry integrated into each ignition coil. The higher voltage is on the compressing cylinder. This is called compression sense ignition. The ICM provides a synthesized cam signal to the PCM based on these inputs. The PCM uses the cam signal to synchronize fuel injection.

This system consists of the following circuits

1. An ignition voltage circuit
2. A ground circuit
3. A camshaft position (CMP) sensor signal circuit
4. An IC timing control circuit for cylinders #1 and #4
5. An IC timing control B circuit for cylinders #2 and #3

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 intake air temperature (IAT) sensor
4. The vehicle speed sensor (VSS)
5. The transmission gear position or range information sensors
6. The engine knock sensors (KS)

Modes of Operation

There is one normal mode of operation during which the PCM controls spark. If the CKP pulses are lost the engine will not run. The loss of a CMP signal may result in a longer crank time since the PCM cannot determine which stroke the pistons are on. Diagnostic trouble codes are available to accurately diagnose the ignition system with a scan tool.

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 sensing
2. Throttle positioning to meet driver and engine demands
3. Throttle position sensing
4. Internal diagnostics
5. Cruise control functions
6. Manage TAC electrical power consumption

The TAC system includes the following components

1. The accelerator pedal position (APP) sensors
2. The throttle body assembly
3. The engine control module (ECM)

Accelerator Pedal Position (APP) Sensor

The accelerator pedal contains 2 individual 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 ECM provides each APP sensor a 5-volt reference circuit and a low reference circuit. The APP sensors provide the ECM 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 ECM 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.

Engine Control Module

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

Normal Mode

During the operation of the 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 ECM updates the learned minimum pedal value.
2. Minimum TP values-At key-up the ECM 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 throttle position, the ice break mode is entered. During the ice break mode, the ECM 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 ECM 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 ECM detects a condition with the TAC system, the ECM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions

1. Acceleration limiting-The ECM will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.
2. Limited throttle mode-The ECM will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.
3. Throttle default mode-The ECM will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.
4. Forced idle mode-The ECM 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 ECM will disable fuel and de-energize the throttle actuator.

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

Sensor Description

This KS system uses one or two flat response two-wire sensors. 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 dependant upon the level of knock that the KS detects. The control module receives the KS signal through a signal circuit. The KS ground is supplied by the control module through a low reference circuit.

The control module 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 control module 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 normal KS signal, keeping the signal within the channel. In order to determine which cylinders are knocking, the control module 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 control module has determined that knock is present, it will retard the ignition timing to attempt to eliminate the knock. The control module 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 control module, the KS wiring, or the KS voltage output. Some diagnostics are also calibrated to detect 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 44062 Injector Test Adapter J 44175 Fuel Composition Tester J 44603 Injector Test Lamp 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
• Fastener Notice
• DTC P0315
• Diagnostic Trouble Code (DTC) List - Vehicle
• Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice
• Exhaust Manifold Replacement
• Lifting and Jacking the Vehicle
• Heated Oxygen and Oxygen Sensor Notice
• Component Fastener Tightening Notice
• Battery Disconnect Caution
• Scheduled Maintenance
• Air Cleaner Outlet Resonator Replacement
• Fuel Pressure Relief Procedure
• Fuel Tank Draining Procedure
• Ignition System Specifications