Engine Controls - 3.6l (ly7) (Introduction) Buick Rendezvous I

Temperature vs Resistance - Engine Coolant Temperature (ECT) Sensor

Temperature vs Resistance - Engine Coolant Temperature (ECT) Sensor

Temperature vs Resistance - Intake Air Temperature (IAT) Sensor

Temperature vs Resistance - Intake Air Temperature (IAT) Sensor

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.

Action Taken When the DTC Sets - Type B1

1. The following applies to misfire DTCs: If the control module detects a low level or an emission level misfire condition during 2 consecutive trips, the control module illuminates the MIL. If the control module detects a high level or catalyst damaging misfire, the control module flashes the MIL at a rate of once per second. If the control module detects a misfire during 2 non-consecutive trips, the stored conditions are compared with the current conditions. The control module illuminates the MIL when the following conditions occur: The engine load is within 10 percent of the previous test that failed. The engine speed is within 375 RPM of the previous test that failed. The engine coolant temperature is in the same range of the previous test that failed.
2. The following applies to fuel trim DTCs: If the control module detects a fuel trim condition during 2 consecutive trips, the control module illuminates the MIL. If the control module detects a fuel trim condition during 2 non-consecutive trips, the stored conditions are compared with the current conditions. The control module illuminates the MIL when the following conditions occur: The engine load is within 10 percent of the previous test that failed. The engine speed is within 375 RPM of the previous test that failed. The engine coolant temperature is in the same range of the previous test that failed.

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

1. The control module turns OFF the MIL after 3 or 4 consecutive ignition cycles depending on the DTC, when the diagnostic runs and does not fail.
2. An active DTC 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 active DTC, clears when the diagnostic runs and passes.
2. Use a scan tool in order to clear the DTC.

Diagnostic Trouble Code (DTC) Type(s)

Diagnostic Trouble Code (DTC) Type(s)

Scheme 2

Scheme 3

Scheme 4

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 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

Scheme 11

Scheme 12

Scheme 13

Scheme 14

Scheme 15

Scheme 16

Scheme 17

Scheme 18

Scheme 19

Scheme 20

Scheme 21

Scheme 22

Scheme 23

Scheme 24

Scheme 25

Scheme 26

Scheme 27

Scheme 28

Engine Control Module (ECM) Connector End Views

Engine Control Module Connector End (ECM) C1 Connector Part Information 1928403379 64-Way F (BLK) Pin Wire Color Circuit No. Function 1 TAN 407 Knock Sensor Low Reference Bank 2 2 - - Not Used 3 LT GRN 5278 HO2S Input Pump Current Bank 1 Sensor 1 4 ORN 5275 Camshaft Position (CMP) Sensor Signal - Intake Bank 1 5 GRY 605 5-Volt Reference 6 - - Not Used 7 TAN 470 Low Reference 8 PPL 486 TP Sensor 2 Signal 9 DK GRN/WHT 2124 Ignition Control 4 10 WHT/BLK 5039 Crankshaft Position (CKP) Sensor Signal 11 - - Not Used 12 ORN/BLK 5272 Camshaft Actuator Solenoid Control - Intake Bank 2 13 LT GRN 5282 Camshaft Actuator Solenoid Control - Exhaust Bank 1 14 - - Not Used 15 BRN 582 TAC Motor Control - 2 16 GRY/WHT 3113 HO2S Heater Control Bank 1 Sensor 1 17 GRY 1716 Knock Sensor Low Reference Bank 1 18 - - Not Used 19 PPL/WHT 1665 HO2S Reference Voltage Bank 1 Sensor 1 20 DK GRN 5273 Camshaft Position (CMP) Sensor Signal - Exhaust Bank 1 21 GRY 23 Generator Field Duty Cycle Signal 22 - - Not Used 23 YEL 410 ECT Sensor Signal 24 - - Not Used 25 LT BLU/WHT 2126 Ignition Control 6 26 ORN/WHT 2122 Ignition Control 2 27-28 - - Not Used 29 PPL 5284 Camshaft Actuator Solenoid Control - Intake Bank 1 30 WHT/BLK 5283 Camshaft Actuator Solenoid Control - Exhaust Bank 2 31 YEL 581 TAC Motor Control - 1 32 - - Not Used 33 DK BLU 496 Knock Sensor Signal Bank 1 34 - - Not Used 35 WHT 5279 HO2S Pump Current Bank 1 Sensor 1 36 PPL 5274 Camshaft Position (CMP) Sensor Signal - Exhaust Bank 2 37 BRN 1174 Engine Oil Level Sensor Signal 38 DK GRN/WHT 357 Engine Oil Temperature Sensor Signal 39 TAN 2752 Low Reference 40 TAN/BLK 231 Engine Oil Pressure Sensor Signal 41 DK GRN 2125 Ignition Control 5 42 PPL 2121 Ignition Control 1 43 ORN 225 Generator Turn On Signal 44 DK BLU/BLK 5041 Intake Manifold Runner Control (IMRC) Solenoid Control 45 DK BLU/BLK 844 Fuel Injector 4 Control 46 PNK/BLK 1746 Fuel Injector 3 Control 47 TAN/WHT 845 Fuel Injector 5 Control 48 LT GRN/WHT 428 EVAP Canister Purge Valve Control 49 GRY/BLK 1798 Engine Ground - Shield 50 LT BLU 1876 Knock Sensor Signal Bank 2 51 - -1 Not Used 52 TAN 1664 HO2S Low Reference Bank 1 Sensor 1 53 YEL 5276 Camshaft Position (CMP) Sensor Signal - Intake Bank 2 54 GRY 2701 5-Volt Reference 55 DK GRN 485 TP Sensor 1 Signal 56 ORN/BLK 5266 BARO Sensor Signal 57 GRY 705 5-Volt Reference 58 LT BLU 2123 Ignition Control 3 59 PPL/WHT 5024 CKP Low Reference 60-61 - - Not Used 62 LT GRN/BLK 1745 Fuel Injector 2 Control 63 TAN 1744 Fuel Injector 1 Control 64 YEL/BLK 846 Fuel Injector 6 Control

Engine Control Module Connector End (ECM) C2 Connector Part Information 1928403386 64-Way F (BLK) Pin Wire Color Circuit No. Function 1 PNK 5290 Ignition 1 Voltage 2 - 3122 Not Used 3 PNK 239 Ignition 1 Voltage 4 DK BLU 473 High Speed Cooling Fan Relay Control 5 WHT 121 Engine Speed Signal 6 - - Not Used 7 WHT/BLK 1164 5-Volt Reference 8 PPL 1272 Low Reference 9 RED/BLK 380 A/C Refrigerant Pressure Sensor Signal 10 WHT 5371 Stop Lamp Switch Signal 11 TAN 472 IAT Sensor Signal 12 DK GRN 890 Fuel Tank Pressure Sensor Signal 13 - - Not Used 14 GRY/BLK 87 Cruise Control Resume/Accel Switch Signal 15 ORN/BLK 463 Requested Torque Signal 16 - - Not Used 17 PNK 5290 Ignition 1 Voltage 18 - - Not Used 19 DK GRN/WHT 465 Fuel Pump Relay Control 20 DK GRN 335 Low Speed Cooling Fan Relay Control 21 - - Not Used 22 DK GRN 389 Vehicle Speed Signal Output 23 TAN/WHT 2500 CAN Serial Data High 24 BRN 5069 Engine Controls Main Relay Control 25 BLK 2759 Low Reference 26 BLK 2760 MAF Sensor Low Reference 27 - - Not Used 28 - - Not Used 29 PPL/WHT 1668 HO2S Signal Bank 1 Sensor 2 30 DK BLU 84 Cruise Control Set/Coast Switch 31 YEL 5 Crank Voltage 32 ORN/BLK 1786 PNP Signal 33 WHT 1310 EVAP Canister Vent Solenoid Control 34 - - Not Used 35 YEL/BLK 625 Starter Relay Control 36 ORN 540 Battery Positive Voltage 37 TAN/BLK 464 Delivered Torque Signal 38 - - Not Used 39 GRY 596 5-Volt Reference 40 BRN 1271 Low Reference 41 - - Not Used 42 PPL 1589 Fuel Level Sensor Signal - Primary 43 YEL 492 MAF Sensor Signal 44 LT BLU 1162 APP Sensor 2 Signal 45 GRY 397 Cruise Control On Switch Signal 46 PPL 420 Cruise Control Release Signal 47 - - Not Used 48 DK GRN 1049 Class 2 Serial Data 49 DK GRN/WHT 459 A/C Clutch Relay Control 50 BRN/WHT 419 MIL Control 51-54 - - Not Used 55 TAN 2501 CAN Serial Data Low 56 TAN 1274 5-Volt Reference 57 TAN/WHT 1669 HO2S Low Reference Sensor 1 58 DK GRN 500 Accessory Voltage 59 - - Not Used 60 DK BLU 1161 APP Sensor Signal 1 61-64 - - Not Used

Engine Controls Connector End Views

Accelerator Pedal Position Connector End (APP) Sensor Connector Part Information 15326829 6-Way F (BLK) Pin Wire Color Circuit No. Function A PPL 1272 Low Reference B LT BLU 1162 APP Sensor 2 Signal C TAN 1274 5-Volt Reference D BRN 1271 Low Reference E DK BLU 1161 APP Sensor 1 Signal F WHT/BLK 1164 5-Volt Reference

Barometric Pressure (BARO) Sensor Connector End Connector Part Information 1928403966 3-Way F (BLK) Pin Wire Color Circuit No. Function 1 GRY 605 5-Volt Reference 2 TAN 470 Low Reference 3 ORN/BLK 5266 BARO Sensor Signal

Camshaft Position (CMP) Actuator Solenoid Connector End - Exhaust Bank 1 Connector Part Information 7283-7526-30 2-Way F (BLK) Pin Wire Color Circuit No. Function 1 WHT 5293 Ignition 1 Voltage 2 LT GRN 5282 Camshaft Actuator Solenoid Control - Exhaust Bank 1

Camshaft Position (CMP) Actuator Solenoid Connector End - Exhaust Bank 2 Connector Part Information 7283-7526-30 2-Way F (BLK) Pin Wire Color Circuit No. Function 1 WHT 5293 Ignition 1 Voltage 2 WHT/BLK 5283 Camshaft Actuator Solenoid Control - Exhaust Bank 2

Camshaft Position (CMP) Actuator Solenoid Connector End - Intake Bank 1 Connector Part Information 7283-7526-30 2-Way F (BLK) Pin Wire Color Circuit No. Function 1 WHT 5293 Ignition 1 Voltage 2 PNK 5284 Camshaft Actuator Solenoid Control - Intake Bank 1

Camshaft Position (CMP) Actuator Solenoid Connector End - Intake Bank 2 Connector Part Information 7283-7526-30 2-Way F (BLK) Pin Wire Color Circuit No. Function 1 WHT 5293 Ignition 1 Voltage 2 ORN/BLK 5252 Camshaft Actuator Solenoid Control - Intake Bank 2

Camshaft Position (CMP) Sensor Connector End - Exhaust Bank 1 Connector Part Information 1928403966 3-Way F (BLK) Pin Wire Color Circuit No. Function 1 TAN 470 Low Reference 2 DK GRN 5273 CMP Sensor Signal Exhaust Bank 1 3 GRY 705 5-Volt Reference

Camshaft Position (CMP) Sensor Connector End - Exhaust Bank 2 Connector Part Information 1928403966 3-Way F (BLK) Pin Wire Color Circuit No. Function 1 TAN 470 Low Reference 2 PPL 5274 CMP Sensor Signal Exhaust Bank 2 3 GRY 705 5-Volt Reference

Camshaft Position (CMP) Sensor Connector End - Intake Bank 1 Connector Part Information 1928403966 3-Way F (BLK) Pin Wire Color Circuit No. Function 1 TAN 470 Low Reference 2 ORN 5275 CMP Sensor Signal Intake Bank 1 3 GRY 705 5-Volt Reference

Camshaft Position (CMP) Sensor Connector End - Intake Bank 2 Connector Part Information 1928403966 3-Way F (BLK) Pin Wire Color Circuit No. Function 1 TAN 470 Low Reference 2 YEL 5276 CMP Sensor Signal Intake Bank 2 3 GRY 705 5-Volt Reference

Crankshaft Position (CKP) Sensor Connector End Connector Part Information 1928403874 2-Way F (BLK) Pin Wire Color Circuit No. Function 1 PPL/WHT 5024 CKP Sensor Low 2 WHT/BLK 5039 CKP Sensor High

Engine Coolant Temperature (ECT) Sensor Connector End Connector Part Information 1928403874 2-Way F (BLK) Pin Wire Color Circuit No. Function 1 YEL 410 ECT Sensor Signal 2 TAN 470 Low Reference

Engine Oil Level/Temperature Sensor Connector End Connector Part Information 15326808 3-Way F (BLK) Pin Wire Color Circuit No. Function A BRN 1174 Oil Level Switch Signal B DK GRN/WHT 357 Oil Temperature Sensor Signal C TAN 470 Low Reference

Engine Oil Pressure (EOP) Sensor Connector End Connector Part Information 12065287 3-Way F (BLK) Pin Wire Color Circuit No. Function A TAN 470 Low Reference B GRY 605 5-Volt Reference C TAN/BLK 231 Oil Pressure Switch Signal

Evaporative Emissions (EVAP) Canister Purge Valve Solenoid Connector End Connector Part Information 1928404072 2-Way F (BLK) Pin Wire Color Circuit No. Function 1 WHT 5293 Ignition 1 Voltage 2 DK GRN/WHT 428 EVAP Canister Purge Solenoid Control

Evaporative Emissions (EVAP) Canister Vent Solenoid Connector End Connector Part Information 12052643 2-Way F (RED) Pin Wire Color Circuit No. Function A RED/WHT 1540 Battery Positive Voltage B WHT 1310 EVAP Canister Vent Solenoid Control

Fuel Injector 1 Connector End Connector Part Information 15305086 2-Way F Metri-Pack 280.1 Series, Sealed (BLK) Pin Wire Color Circuit No. Function A WHT 5291 Ignition 1 Voltage B TAN 1744 Fuel Injector 1 Control

Fuel Injector 2 Connector End Connector Part Information 15305086 2-Way F Metri-Pack 280.1 Series, Sealed (BLK) Pin Wire Color Circuit No. Function A WHT 5292 Ignition 1 Voltage B LT GRN/BLK 1745 Fuel Injector 2 Control

Fuel Injector 3 Connector End Connector Part Information 15305086 2-Way F Metri-Pack 280.1 Series, Sealed (BLK) Pin Wire Color Circuit No. Function A WHT 5291 Ignition 1 Voltage B PNK/BLK 1746 Fuel Injector 3 Control

Fuel Injector 4 Connector End Connector Part Information 15305086 2-Way F Metri-Pack 280.1 Series, Sealed (BLK) Pin Wire Color Circuit No. Function A WHT 5292 Ignition 1 Voltage B LT BLU/BLK 844 Fuel Injector 4 Control

Fuel Injector 5 Connector End Connector Part Information 15305086 2-Way F Metri-Pack 280.1 Series, Sealed (BLK) Pin Wire Color Circuit No. Function A WHT 5291 Ignition 1 Voltage B TAN/WHT 845 Fuel Injector 5 Control

Fuel Injector 6 Connector End Connector Part Information 15305086 2-Way F Metri-Pack 280.1 Series, Sealed (BLK) Pin Wire Color Circuit No. Function A WHT 5292 Ignition 1 Voltage B YEL/BLK 846 Fuel Injector 6 Control

Fuel Pump and Sender Assembly Connector End Connector Part Information 12160482 4-Way F (BLK) Pin Wire Color Circuit No. Function A LT BLU 1937 Fuel Gage Sensor Signal - Primary B GRY 120 Fuel Pump Supply Voltage C BLK 1050 Ground D TAN 452 Low Reference

Fuel Tank Pressure (FTP) Sensor Connector End Connector Part Information 12059595 3-Way F (BLK) Pin Wire Color Circuit No. Function A TAN 452 Low Reference B DK GRN 890 Fuel Tank Pressure Sensor Signal C GRY 596 5-Volt Reference

Heated Oxygen Sensor (HO2S) Sensor 1 Connector End Connector Part Information 12092839 4-Way M (BLK) Pin Wire Color Circuit No. Function A TAN/WHT 1669 HO2S Low Signal Sensor 1 B PPL/WHT 1668 HO2S High Signal Sensor 1 D PNK/BLK 5294 Ignition 1 Voltage E GRY/WHT 3122 HO2S Heater Low Control Sensor 1

Heated Oxygen Sensor (HO2S) Sensor 2 Connector End Connector Part Information 12092839 4-Way M (BLK) Pin Wire Color Circuit No. Function A TAN 1671 HO2S Low Signal Sensor 2 B PPL 1670 HO2S High Signal Sensor 2 D PNK/BLK 5294 Ignition 1 Voltage E GRY/WHT 3223 HO2S Heater Low Control Sensor 2

Ignition Coil 1 Connector End Connector Part Information 1928403441 4-Way F (BLK) Pin Wire Color Circuit No. Function 1 PPL 2121 IC 1 Control 2 WHT 5291 Ignition 1 Voltage 3 BLK/WHT 1551 Ground 4 BLK 1550 Ground

Ignition Coil 2 Connector End Connector Part Information 1928403441 4-Way F (BLK) Pin Wire Color Circuit No. Function 1 ORN/WHT 2122 IC 2 Control 2 WHT 5292 Ignition 1 Voltage 3 BLK/WHT 151 Ground 4 BLK 150 Ground

Ignition Coil 3 Connector End Connector Part Information 1928403441 4-Way F (BLK) Pin Wire Color Circuit No. Function 1 LT BLU 2123 IC 3 Control 2 WHT 5291 Ignition 1 Voltage 3 BLK/WHT 1551 Ground 4 BLK 1550 Ground

Ignition Coil 4 Connector End Connector Part Information 1928403441 4-Way F (BLK) Pin Wire Color Circuit No. Function 1 DK GRN/WHT 2124 IC 4 Control 2 WHT 5292 Ignition 1 Voltage 3 BLK/WHT 151 Ground 4 BLK 150 Ground

Ignition Coil 5 Connector End Connector Part Information 1928403441 4-Way F (BLK) Pin Wire Color Circuit No. Function 1 DK GRN 2125 IC 5 Control 2 WHT 5291 Ignition 1 Voltage 3 BLK/WHT 1551 Ground 4 BLK 1550 Ground

Ignition Coil 6 Connector End Connector Part Information 1928403441 4-Way F (BLK) Pin Wire Color Circuit No. Function 1 LT BLU/WHT 2126 IC 6 Control 2 WHT 5292 Ignition 1 Voltage 3 BLK/WHT 151 Ground 4 BLK 150 Ground

Intake Manifold Runner Control (IMRC) Solenoid Connector End Connector Part Information 7283-8226-30 2-Way F (BLK) Pin Wire Color Circuit No. Function 1 LT BLU/WHT 5041 Intake Manifold - Output 1 2 WHT 5293 Ignition 1 Voltage

Knock Sensor (KS) Bank 1 Connector End Connector Part Information 1928403874 2-Way F (BLK) Pin Wire Color Circuit No. Function 1 DK BLU 496 Knock Sensor Bank 1 Signal 2 GRY 1716 Low Reference

Knock Sensor (KS) Bank 2 Connector End Connector Part Information 1928403874 2-Way F (BLK) Pin Wire Color Circuit No. Function 1 LT BLU 1876 Knock Sensor Bank 2 Signal 2 TAN 407 Low Reference

Mass Air Flow (MAF) Sensor Connector End Connector Part Information 1928403200 5-Way F (BLK) Pin Wire Color Circuit No. Function 1 TAN 472 IAT Sensor Signal 2 PNK 739 Ignition 1 Voltage 3 BLK 2760 Low Reference 4 GRY 596 5-Volt Reference 5 YEL 492 MAF Sensor Signal

Throttle Body Assembly Connector End Connector Part Information 1-967616-1 6-Way F (BLK) Pin Wire Color Circuit No. Function 1 YEL 581 TAC Motor Control 1 2 TAN 2752 Low Reference 3 GRY 2701 5-Volt Reference 4 TAN 582 TAC Motor Control 2 5 PPL 486 TP Sensor 2 Signal 6 DK GRN 485 TP Sensor 1 Signal

Removal Procedure

Note. Always turn the ignition off when installing or removing the ECM connectors in order to prevent damage to the components.

Scheme 29

1. Using a scan tool, retrieve the percentage of remaining engine oil. Record the remaining engine oil life.
2. Turn the ignition OFF.
3. Use a DVOM in order to measure the main relay circuit voltage at the engine control module (ECM) fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/rendezvous/i-2001-2007/remont/electrical-component-locations/#wiring-systems-component-locator) in Wiring Systems.
4. Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (LA1)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
5. Remove the ECM fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/rendezvous/i-2001-2007/remont/electrical-component-locations/#wiring-systems-component-locator) in Wiring Systems.
6. Remove the transmission control module/instrument panel cluster (TCM/IPCM) fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/rendezvous/i-2001-2007/remont/electrical-component-locations/#wiring-systems-component-locator) in Wiring Systems.
7. Remove the ECM/TCM fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/rendezvous/i-2001-2007/remont/electrical-component-locations/#wiring-systems-component-locator) in Wiring Systems.
8. Unlock the body side (outboard) ECM electrical connector. Depress the ECM electrical connector lever lock (1). Simultaneously rotate the ECM connector clamp lever and depress the lock slide (2).
9. Remove the body side (outboard) ECM connector.
10. Unlock and remove the engine side (inboard) ECM connector.
11. Remove the ECM redundant ground wire and bolt from the ECM.
12. Remove the ECM bolts.
13. Remove the ECM.
14. If necessary, perform the following steps: Remove the ECM bracket bolts. Remove the ECM bracket.

Installation Procedure

1. Install the ECM bracket, as necessary.
2. Install the ECM bracket bolts. Tighten: Tighten the ECM bracket bolts to 10 N.m (89 lb in).
3. Install the ECM.
4. Install the ECM bolts. Tighten: Tighten the ECM bolts to 10 N.m (89 lb in).
5. Install the ECM redundant ground and bolt to the ECM. Tighten: Tighten the ECM redundant ground wire bolt to 5 N.m (44 lb in).
6. Install the engine side (inboard) ECM connector.
7. Install the body side (outboard) ECM connector.
8. Install the ECM/TCM fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/rendezvous/i-2001-2007/remont/electrical-component-locations/#wiring-systems-component-locator) in Wiring Systems.
9. Install the TCM/IPC fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/rendezvous/i-2001-2007/remont/electrical-component-locations/#wiring-systems-component-locator) in Wiring Systems.
10. Install the ECM fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/rendezvous/i-2001-2007/remont/electrical-component-locations/#wiring-systems-component-locator) in Wiring Systems.
11. Connect the battery negative cable to the battery. Refer to «Battery Negative Cable Disconnect/Connect Procedure (LA1)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
12. Program the ECM. Refer to «Service Programming System (SPS)»(/buick/rendezvous/i-2001-2007/remont/communication-devices/#service-programming-system) in Programming and Setup.
13. Turn OFF the ignition for at least 5 seconds after the programming event is complete.
14. Perform the idle learn procedure. Refer to «Idle Learn Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction__idle-learn-procedure) .
15. Use the scan tool to clear all DTCs.

Description

The engine control module (ECM) learns the idle position of the throttle body to ensure the correct idle operation. Anytime the ECM or the throttle body is replaced, the ECM must learn the idle position. The engine idle may be unstable or a DTC may set if the idle position is not learned.

Conditions for Running the Idle Learn Procedure

1. DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0638, P2100, P2101, P2105, P2107, and P2119 are not set.
2. The engine speed is less than 40 RPM.
3. The vehicle speed is 0 km/h (0 mph).
4. The accelerator pedal position is less than 14.9 percent.
5. The ignition 1 voltage is more than 10 volts.
6. The engine coolant temperature is between 5-60°C (41-140°F).
7. The intake air temperature is between 5-60°C (41-140°F).

Idle Learn Procedure

1. Turn OFF the ignition for 30 seconds.
2. Turn ON the ignition, with the engine OFF for 60 seconds.
3. Turn OFF the ignition.
4. Turn ON the ignition, with the engine OFF.
5. Clear the DTCs with a scan tool.

1. Turn the ignition OFF.
2. Partially drain the cooling system. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) in Engine Cooling.
3. Remove the coolant temperature sensor electrical connector.
4. Remove the coolant temperature sensor.

1. Install the coolant temperature sensor. Tighten: Tighten the sensor to 22 N.m (16 lb ft).
2. Install the coolant temperature sensor electrical connector.
3. Inspect and fill the cooling system as necessary. Refer to «Draining and Filling Cooling System»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) in Engine Cooling.

1. Turn the ignition OFF.
2. Remove the mass air flow (MAF) electrical connector.
3. Remove the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
4. Remove the MAF sensor screws.
5. Remove the MAF sensor and the MAF sensor seal.

1. Install the MAF sensor seal to the air cleaner cover.
2. Lubricate the seal with clean water.
3. Install the MAF sensor to the air cleaner cover.
4. Install the MAF sensor screws. Tighten: Tighten the MAF sensor screws to 4 N.m (35 lb in).
5. Install the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
6. Install the MAF sensor electrical connector.

1. Turn the ignition OFF.
2. Remove the sensor electrical connector.
3. Remove the barometric pressure sensor bolt.
4. Remove the barometric pressure sensor.

1. Install the barometric pressure sensor.
2. Install the barometric pressure sensor bolt. Tighten: Tighten the barometric pressure sensor bolt to 10 N.m (89 lb in).
3. Install the sensor electrical connector.

Note. The Heated Oxygen Sensor (HO2S) and the Oxygen Sensor use a permanently attached pigtail and connector. Do not remove this pigtail from the Heated Oxygen Sensor. Damage or the removal of the pigtail or the connector could affect the proper operation of the sensor. Take care when handling the HO2S and the O2S. Keep the in-line electrical connector and the louvered end free of grease, dirt, or other contaminants. Also avoid using cleaning solvents of any type. Do not drop the HO2S or the O2S. Do not roughly handle the HO2S or the O2S.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Disconnect the intermediate steering shaft from the steering gear. Refer to «Intermediate Steering Shaft Replacement»(/buick/rendezvous/i-2001-2007/remont/ignition-switchsteering-lock/#steering-wheel-steering-column) in Steering Wheel and Column.
3. Remove and reposition the front portion of the front fender liners in order to gain access to the frame front bolts. Refer to «Front Fender Liner Replacement»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
4. Lower the vehicle.
5. Position a floor jack at the front center section of the frame in order to support the powertrain.
6. Remove the frame front bolts.
7. Carefully lower the powertrain or raise the vehicle in order to gain access to the oxygen sensor.
8. Disconnect the oxygen sensor electrical connector.
9. Remove the heated oxygen sensor (HO2S).

1. Install the HO2S. Tighten: Tighten the HO2S 1 to 42 N.m (31 lb ft).
2. Connect the oxygen sensor electrical connector.
3. Use the floor jack in order to raise the powertrain until the frame insulators contact the chassis.
4. Install the frame front bolts. Refer to «Frame Replacement - Front (W/AWD)»(/buick/rendezvous/i-2001-2007/remont/frames-subframes-crossmembers/#frame-and-underbody) or «Frame Replacement - Front (W/FWD)»(/buick/rendezvous/i-2001-2007/remont/frames-subframes-crossmembers/#frame-and-underbody) in Frame and Underbody.
5. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
6. Install and reposition the front portion of the front fender liners in order to gain access to the frame front bolts. Refer to «Front Fender Liner Replacement»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
7. Connect the intermediate steering shaft to the steering gear. Refer to «Intermediate Steering Shaft Replacement»(/buick/rendezvous/i-2001-2007/remont/ignition-switchsteering-lock/#steering-wheel-steering-column) in Steering Wheel and Column.
8. Lower the vehicle.

Note. The Heated Oxygen Sensor (HO2S) and the Oxygen Sensor use a permanently attached pigtail and connector. Do not remove this pigtail from the Heated Oxygen Sensor. Damage or the removal of the pigtail or the connector could affect the proper operation of the sensor. Take care when handling the HO2S and the O2S. Keep the in-line electrical connector and the louvered end free of grease, dirt, or other contaminants. Also avoid using cleaning solvents of any type. Do not drop the HO2S or the O2S. Do not roughly handle the HO2S or the O2S.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Disconnect the heated oxygen sensor (HO2S) electrical connector.
3. Remove the HO2S.

1. Install the HO2S. Tighten: Tighten the HO2S 2 to 42 N.m (31 lb ft).
2. Connect the HO2S electrical connector.
3. Lower the vehicle.

1. Turn the ignition OFF.
2. Remove the closeout/insulator panel from under the dashboard on the drivers side. Refer to «Closeout/Insulator Panel Replacement - Left»(/buick/rendezvous/i-2001-2007/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages, and Console.
3. Disconnect the accelerator pedal position (APP) sensor electrical connector from the accelerator pedal module.
4. Remove the APP sensor mounting bolts.
5. Remove the APP sensor from the vehicle.

1. Position the APP sensor to the mounting plate.
2. Install the APP sensor mounting bolts. Tighten: Tighten the APP sensor mounting bolts to 10 N.m (89 lb in).
3. Connect the APP sensor electrical connector.
4. Operate the accelerator pedal and observe the APP angles using a scan tool. The accelerator pedal should operate freely, without binding between closed throttle and wide open throttle.
5. Install the closeout/insulator panel. Refer to «Closeout/Insulator Panel Replacement - Left»(/buick/rendezvous/i-2001-2007/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.

1. Turn the ignition OFF.
2. Remove the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
3. Remove the throttle body electrical connector.
4. Remove the throttle body bolts.
5. Remove the throttle body and gasket.

1. Carefully clean the throttle body mounting surfaces of any gasket and/or seal material.
2. Install the throttle body and NEW gasket.
3. Install the throttle body bolts. Tighten: Tighten the throttle body bolts to 10 N.m (89 lb in).
4. Install the throttle body electrical connector.
5. Install the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
6. Perform the idle learn procedure. Refer to «Idle Learn Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction__idle-learn-procedure) .
7. Use the scan tool to clear all DTCs.

Throttle Body Service

1. Remove the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
2. Fully open the throttle valve in order to Inspect the throttle body bore and the throttle valve plate for any deposits.
3. Use a clean shop towel and Top Engine Cleaner GM P/N 1052626 or equivalent product in order to clean the throttle body bore and the throttle valve plate. If necessary, use a parts cleaning brush in order to remove heavy deposits.
4. Install the air cleaner duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .

Fuel Pressure Relief Procedure

1. Turn the ignition OFF.
2. Remove the fuel pump fuse and the fuel pump relay. Refer to «Electrical Center Identification Views»(/buick/rendezvous/i-2001-2007/remont/electrical-component-locations/#wiring-systems-component-locator) in Wiring Systems.
3. Loosen the fuel filler cap to relieve the fuel tank vapor pressure.
4. Attempt to start the engine and allow the engine to run until it stops.
5. Remove the fuel pressure test port cap.
6. Wrap a shop towel around the fuel pressure test port and use a small flat-bladed tool in order to depress (open) the fuel pressure test port valve.
7. Place the shop towel in an approved container.
8. Install the fuel pressure test port cap.
9. Tighten the fuel filler cap.

1. Relieve the fuel pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction__fuel-pressure-relief-procedure) .
2. Remove the fuel pressure test port cap.
3. Install the fuel pressure gage to the fuel pressure test port.
4. Place the shop towel in an approved container.
5. Perform any tests and/or diagnostics as needed.

1. Relieve the fuel pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction__fuel-pressure-relief-procedure) .
2. Remove the fuel pressure gage.
3. Place the shop towel in an approved container.
4. Install the fuel pressure test port cap.

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction__fuel-pressure-relief-procedure) .
2. Remove the retainer from the quick-connect fitting.
3. Use compressed air in order to remove any debris from the fitting.
4. Use Snap-On® ACT1370 Disconnect Set or equivalent in order to disconnect the fuel line.
5. Using a clean shop towel, wipe off the male pipe end.
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 to install the fuel line.
3. Pull the fuel hose in order to ensure that the fitting is secure.
4. Install the retainer to the quick-connect fitting.
5. Inspect for leaks using the following procedure: Turn the ignition ON, with the engine OFF for 2 seconds. Turn the ignition OFF, for 10 seconds. Turn the ignition ON, with the engine OFF for 2 seconds. Turn the ignition OFF. Inspect for leaks.

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction__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. Using a clean shop towel, wipe off the male pipe end
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 to cause the retaining tabs/fingers to snap into place.
3. Pull on both sides of the quick-connect fitting to make sure the connection is secure.
4. Inspect for leaks using the following procedure: Turn the ignition ON, with the engine OFF for 2 seconds. Turn the ignition OFF, for 10 seconds. Turn the ignition ON, with the engine OFF for 2 seconds. Turn the ignition OFF. Inspect for leaks.

Tools Required

1. J 42960-2 Fuel Flapper Door Holder
2. J 45004 Fuel Tank Drain Hose

1. Remove the fuel filler cap.
2. Install the J 42960-2 into the fuel fill pipe in order to hold the door open.
3. Insert the J 45004 into the fuel tank until the hose reaches the bottom of the fuel tank.
4. Use an air operated pump device in order to drain as much fuel through the fuel fill pipe as possible.

1. Relieve the fuel system fuel pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction__fuel-pressure-relief-procedure) .
2. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) .
3. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Disconnect the fuel tank wiring harness connector (1).
5. Disconnect the fuel evaporative emission (EVAP) pipes. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
6. Remove the EVAP canister bracket nut.
7. Loosen the fuel tank fill pipe hose clamp.
8. Disconnect the fuel tank fill pipe hose (2) from the fuel tank (1).
9. Disconnect the EVAP vent pipe near the fill pipe hose. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
10. With the aid of an assistant or a transmission jack, support the fuel tank and remove the fuel tank strap attaching bolts (2).
11. Remove the fuel tank from the vehicle and place the fuel tank in a suitable work area.
12. If the fuel tank is being replaced, perform the following steps: Remove the fuel sender (1). Refer to «Fuel Tank Module Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) . Remove the fuel tank wiring harness from the fuel tank. Remove the fuel pipes from the fuel tank. Remove the EVAP vent solenoid valve (2). Refer to «Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) . Remove the EVAP canister (3). Refer to «Evaporative Emission (EVAP) Canister Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .

1. Install the EVAP canister (3). Refer to «Evaporative Emission (EVAP) Canister Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
2. Install the EVAP vent solenoid valve (2). Refer to «Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
3. Install the fuel pipes to the fuel tank.
4. Install the fuel tank wiring harness to the fuel tank.
5. Install the fuel sender (1). Refer to «Fuel Tank Module Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
6. With the aid of an assistant or a transmission jack, position and support the fuel tank.
7. Install the fuel tank strap bolts (2). Tighten: Tighten the fuel tank strap bolts to 47 N.m (35 lb ft).
8. Install the EVAP canister bracket nut. Tighten: Tighten the EVAP canister bracket nut to 6 N.m (53 lb in).
9. Install the EVAP vent pipe near the fill pipe hose. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
10. Install the fuel tank filler pipe hose (2) to the fuel tank (1). Tighten: Tighten the fuel tank filler pipe hose clamp to 2.5 N.m (22 lb in).
11. Connect the fuel pipes.
12. Install the fuel tank wiring harness connector (1).
13. Lower the vehicle.
14. Add fuel as necessary and install the fuel tank filler pipe cap.
15. Inspect for fuel leaks. Perform the following steps: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.

1. Remove the fuel tank. Refer to «Fuel Tank Replacement (Prior to VIN 4S558922 (100mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) or «Fuel Tank Replacement (VIN 4S558922 and Later (130mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) .
2. Disconnect the electrical connector from the fuel tank vapor pressure sensor.
3. Remove the fuel tank pressure sensor from the fuel sender.

1. Install the new fuel tank pressure sensor to the fuel sender.
2. Connect the electrical connector to fuel tank vapor pressure sensor.
3. Install the fuel tank. Refer to «Fuel Tank Replacement (Prior to VIN 4S558922 (100mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) or «Fuel Tank Replacement (VIN 4S558922 and Later (130mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement__fuel-pressure-relief-procedure) .
2. Remove the fuel filler cap.
3. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) .
4. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
5. Remove the fuel filler pipe nuts (1).
6. Remove the fuel filler pipe bolt (2).
7. Loosen the fuel filler pipe clamp.
8. Remove the fuel filler pipe hose (2) from the fuel tank (1).
9. Disconnect the vent pipe near the fill pipe hose.
10. Remove the fuel filler pipe from the fuel filler pocket.

1. Install the fuel filler pipe through the fuel filler pocket.
2. Connect the vent pipe near the fill pipe hose.
3. Install the fuel filler pipe (2) to the fuel tank (1). Fully seat the fill pipe to stop on the tank. Tighten: The fuel filler pipe hose clamp to 2.5 N.m (22 lb in).
4. Install the fuel filler pipe bolt (2). Tighten: The fuel filler pipe bolt to 25 N.m (18 lb ft).
5. Install the fuel filler pipe nuts (1). Tighten: Tighten the fuel filler pipe nut to 6 N.m (53 lb in).
6. Lower the vehicle.
7. Refill the fuel tank.
8. Tighten the fuel filler cap.
9. Reconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (LA1)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
10. Inspect for fuel leaks with the following procedure: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.

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

1. Remove the fuel tank. Refer to «Fuel Tank Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
2. Disconnect the fuel sender module electrical connectors.
3. Disconnect the fuel pipes from the fuel sender. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
4. Use the J 45722 (1) and a long breaker-bar in order to unlock the fuel sender lock ring. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
5. Remove the fuel sender lock ring (1) and the fuel sender (2) from the fuel tank.
6. Remove and discard the fuel sender seal (3).
7. Remove the fuel level sensor from the fuel sender module. Refer to «Fuel Tank Pressure Sensor Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .

1. Install the fuel level sensor to the fuel sender module. Refer to «Fuel Tank Pressure Sensor Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
2. Clean the fuel sender sealing flange.
3. Install the NEW fuel sender seal (3) to the fuel tank seal groove.
4. Install the fuel sender (2) and the fuel sender lock ring (1).
5. Use the J 45722 (1) in order to install the fuel sender lock ring. See «Special Tools and Equipment»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
6. Install the fuel pipes to the fuel sender. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
7. Install the fuel sender sensor electrical connectors.
8. Install the fuel tank. Refer to «Fuel Tank Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .

1. Remove the fuel sender from the fuel tank. Refer to «Fuel Tank Module Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
2. Disconnect the fuel level sensor electrical connector located in the module cover.
3. Use a small flat-bladed tool in order to disengage the fuel level sensor retainer.
4. Slide the fuel level sensor down in order to remove the fuel level sensor from the fuel sender module.

1. Slide the fuel level sensor up in order to install the fuel level sensor to the fuel sender module.
2. Ensure that the fuel level sensor retainer is properly engaged.
3. Connect the fuel level sensor electrical connector.
4. Install the fuel sender to the fuel tank. Refer to «Fuel Tank Module Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement__fuel-pressure-relief-procedure) .
2. Clean all engine fuel pipe connections.
3. Clean areas surrounding the engine fuel pipe connections.
4. Disconnect the fuel feed and evaporative emission (EVAP) pipes from the engine. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) and «Quick Connect Fitting(s) Service (Metal Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
5. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
6. Disconnect the fuel feed and EVAP pipes from the fuel tank. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) .
7. Cap the fuel pipes in order to stop any fuel leakage.
8. Remove the fuel pipe retainers with the fuel pipes.
9. Note the position of the fuel and EVAP pipes and the fuel and EVAP pipe attaching hardware for installation.
10. Inspect the pipes for bends, kinks, and cracks.
11. Replace the pipe or pipes as required.

1. Install the fuel pipe attaching hardware as noted during removal.
2. Remove the caps from the fuel pipes.
3. Connect the fuel feed and EVAP pipes to the fuel tank. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) .
4. Lower the vehicle.
5. Connect the fuel feed and EVAP pipes to the engine. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) and «Quick Connect Fitting(s) Service (Metal Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
6. Lower the vehicle.
7. Tighten the fuel fill cap.
8. Reconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (LA1)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
9. Inspect for fuel leaks with the following procedure: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.

1. Turn the ignition OFF.
2. Remove the air inlet duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
3. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction__fuel-pressure-relief-procedure) .
4. Remove the fuel pressure and evaporative emission (EVAP) hoses from the engine. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) and «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
5. Remove the purge line from the purge line retainer.
6. Remove the throttle body. Refer to «Throttle Body Assembly Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
7. Remove the fuel feed hose bracket bolt.
8. Use the Snap-On® ACT1370 Disconnect Set or equivalent to disconnect the fuel feed hose from the fuel rail.
9. Carefully remove the purge line retainer from the fuel feed hose bracket as necessary.

1. Install the purge line retainer to the fuel feed hose bracket as necessary.
2. Install the fuel feed hose to the fuel rail.
3. Install the fuel feed hose bracket and the fuel feed hose bracket bolt. Tighten: Tighten the fuel feed hose bracket bolt to 10 N.m (89 lb in).
4. Install the purge line to the purge line retainer.
5. Install the fuel pressure and EVAP hoses to the engine. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) and «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
6. Install the air inlet duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .

Fuel System Cleaning

1. Relieve the fuel system fuel pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement__fuel-pressure-relief-procedure) .
2. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) .
3. Remove the fuel tank. Refer to «Fuel Tank Replacement (Prior to VIN 4S558922 (100mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) or «Fuel Tank Replacement (VIN 4S558922 and Later (130mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) .
4. Remove the fuel sender assembly. Refer to «Fuel Sender Assembly Replacement (Prior to VIN 4S558922 (100mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) or «Fuel Sender Assembly Replacement (VIN 4S558922 and Later (130mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) .
5. Inspect the fuel pump inlet for dirt and debris. If dirt and debris are found, the fuel pump needs to be replaced.
6. Flush the fuel tank with hot water.
7. 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.
8. Allow the tank to dry completely before reassembly.
9. Install the fuel sender assembly. Refer to «Fuel Sender Assembly Replacement (Prior to VIN 4S558922 (100mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) or «Fuel Sender Assembly Replacement (VIN 4S558922 and Later (130mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) .
10. Install the fuel tank. Refer to «Fuel Tank Replacement (Prior to VIN 4S558922 (100mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) or «Fuel Tank Replacement (VIN 4S558922 and Later (130mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) .
11. Add fuel and install the fuel tank filler pipe cap.
12. Inspect for fuel leaks using the following procedure: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction__fuel-pressure-relief-procedure) .
2. Remove the upper intake manifold. Refer to «Intake Manifold Replacement - Upper»(/buick/rendezvous/i-2001-2007/remont/mechanical/#engine-mechanical-repair-instructions-1-of-5-36l-ly7) in Engine Mechanical - 3.6L (LY7).
3. Remove the fuel pipe retaining clip.
4. Use compressed air in order to remove debris from the area where the fuel injectors enter the intake manifold.
5. Remove the fuel rail bolts.
6. Remove the fuel rail with the fuel injectors.
7. Disengage the fuel injector electrical connector lock (1).
8. Disconnect the fuel injector electrical connector.
9. Remove the fuel injector retainer clip.
10. Remove the fuel injector.
11. Remove and discard the fuel injector seals.

1. Install NEW fuel injector seals.
2. Install the fuel injector.
3. Install the fuel injector retainer clip.
4. Install the fuel injector electrical connector.
5. Engage the fuel injector electrical connector lock.
6. Install the fuel rail with the fuel injectors.
7. Install the fuel rail bolts. Tighten: Tighten the fuel rail bolts to 10 N.m (89 lb in).
8. Install the upper intake manifold. Refer to «Intake Manifold Replacement - Upper»(/buick/rendezvous/i-2001-2007/remont/mechanical/#engine-mechanical-repair-instructions-1-of-5-36l-ly7) in Engine Mechanical - 3.6L (LY7).

Fuel Injector Cleaning Procedure

Tools Required

1. J 37287 Fuel Line Shut-Off Adapters
2. J 35800-A Fuel Injector Cleaner
3. J 42873-1 3/8 Fuel Line Shut-Off Valve
4. J 42873-2 5/16 Return Pipe Shut-Off Valve
5. J 42964-1 3/8 Fuel Pipe Shut-Off Valve
6. J 42964-2 5/16 Fuel Pipe Shut-Off Valve

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.
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.
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.

1. Turn the ignition OFF.
2. Disconnect the purge line from the purge valve solenoid.
3. Disconnect the purge valve solenoid electrical connector.
4. Disconnect the purge line from the manifold side of the purge valve solenoid.
5. Remove the purge valve solenoid and bolt from the intake manifold.

1. Install the purge valve solenoid to the intake manifold. Tighten: Tighten the purge solenoid bolt to 10 N.m (89 lb in).
2. Connect the purge line to the manifold side of the purge valve solenoid.
3. Disconnect the purge valve solenoid electrical connector.
4. Connect the purge line to the purge valve solenoid.

1. Remove the fuel tank. Refer to «Fuel Tank Replacement (Prior to VIN 4S558922 (100mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) or «Fuel Tank Replacement (VIN 4S558922 and Later (130mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) .
2. Disconnect the evaporative emission (EVAP) canister vent solenoid harness connector.
3. Remove the EVAP vent hose from EVAP canister solenoid.
4. Depress the EVAP canister vent bracket tab to release the EVAP canister vent solenoid.
5. Remove the EVAP canister solenoid from the fuel tank.

1. Slide the EVAP canister vent solenoid on the EVAP canister vent bracket until the solenoid snaps into place.
2. Connect the EVAP vent hose to the EVAP canister vent solenoid.
3. Connect the EVAP canister vent solenoid harness connector.
4. Install the fuel tank. Refer to «Fuel Tank Replacement (Prior to VIN 4S558922 (100mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) or «Fuel Tank Replacement (VIN 4S558922 and Later (130mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) .

1. Disconnect the evaporative emission (EVAP) purge hose from the purge line near the throttle body. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
2. Remove the EVAP purge hose from the retainer.
3. Remove the EVAP purge pipe from the intake manifold.
4. Remove the EVAP purge hose from the EVAP purge valve and the intake manifold.
5. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
6. Disconnect the EVAP purge from the fuel tank.
7. Disconnect the EVAP purge pipe from the fuel pipe retainers.
8. Remove the EVAP purge pipe from the vehicle.

1. Install the EVAP purge pipe from the vehicle.
2. Install the EVAP purge pipe to the retainers.
3. Connect the chassis EVAP purge pipe to the fuel tank.
4. Lower the vehicle.
5. Install the EVAP purge hose to the EVAP purge valve and the intake manifold. Tighten: Tighten the EVAP purge hose bracket bolt to 10 N.m (89 lb in).
6. Install the EVAP purge pipe to the intake manifold.
7. Install the EVAP purge hose to the retainer.
8. Connect the EVAP hose to the purge line near the throttle body. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .

1. Remove the evaporative emission (EVAP) canister front bracket nut.
2. Remove the EVAP canister nuts and the EVAP canister bracket.
3. Reposition the EVAP canister and disconnect the EVAP hoses and/or pipes from the EVAP canister.
4. Remove the EVAP canister.

1. Install the EVAP canister.
2. Connect the EVAP hoses/pipes to the EVAP canister.
3. Install the EVAP canister bracket and the EVAP canister nuts. Tighten: Tighten the EVAP canister nuts to 10 N.m (89 lb in).
4. Install the EVAP canister bracket nut. Tighten: Tighten the EVAP canister bracket nut to 6 N.m (53 lb in).
5. Install the fuel tank. Refer to «Fuel Tank Replacement (Prior to VIN 4S558922 (100mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement) or «Fuel Tank Replacement (VIN 4S558922 and Later (130mm Sender))»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-introduction-service-replacement)

1. Turn the ignition OFF.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Disconnect the intermediate steering shaft from the steering gear. Refer to «Intermediate Steering Shaft Replacement»(/buick/rendezvous/i-2001-2007/remont/ignition-switchsteering-lock/#steering-wheel-steering-column) in Steering Wheel and Column.
4. Remove and reposition the front portion of the front fender liners in order to gain access to the frame front bolts. Refer to «Front Fender Liner Replacement»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
5. Lower the vehicle.
6. Position a floor jack at the front center section of the frame in order to support the powertrain.
7. Remove the frame front bolts.
8. Carefully lower the powertrain in order to provide access.
9. Reposition the evaporative emission (EVAP) purge hoses as necessary in order to provide access.
10. Disconnect the applicable ignition coil electrical connectors.
11. Remove the ignition coil bolts.
12. Remove the ignition coils.

1. Install the ignition coils.
2. Install the ignition coil bolts. Tighten: Tighten the ignition coil bolts to 10 N.m (89 lb in).
3. Connect the ignition coil electrical connectors.
4. Use the floor jack in order to raise the powertrain until the frame contacts the chassis.
5. Install the frame front bolts. Refer to «Frame Replacement - Front (W/AWD)»(/buick/rendezvous/i-2001-2007/remont/frames-subframes-crossmembers/#frame-and-underbody) or «Frame Replacement - Front (W/FWD)»(/buick/rendezvous/i-2001-2007/remont/frames-subframes-crossmembers/#frame-and-underbody) in Frame and Underbody.
6. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
7. Install the front fender liners. Refer to «Front Fender Liner Replacement»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
8. Connect the intermediate steering shaft to the steering gear. Refer to «Intermediate Steering Shaft Replacement»(/buick/rendezvous/i-2001-2007/remont/ignition-switchsteering-lock/#steering-wheel-steering-column) in Steering Wheel and Column.
9. Lower the vehicle.

1. Turn the ignition OFF.
2. Disconnect the applicable ignition coil electrical connector(s).
3. Remove the ignition coil bolt(s).
4. Remove the ignition coil(s).

1. Install the ignition coil(s).
2. Install the ignition coil bolt(s). Tighten: Tighten the ignition coil bolt(s) to 10 N.m (89 lb in).
3. Connect the ignition coil electrical connector(s).

Spark Plug Inspection

Spark Plug Usage

1. Ensure that the correct spark plug is installed. An incorrect spark plug causes driveability conditions. Refer to «Ignition System Specifications»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction__ignition-system-specifications) for the correct spark plug.
2. Ensure that the spark plug has the correct heat range. An incorrect heat range causes the following conditions: Spark plug fouling-Colder plug Pre-ignition causing spark plug and/or engine damage-Hotter plug

Spark Plug Inspection

1. Inspect the terminal post (1) for damage. Inspect for a bent or broken terminal post (1). Test for a loose terminal post (1) by twisting and pulling the post. The terminal post (1) should NOT move.
2. Inspect the insulator (2) for flashover or carbon tracking, soot. This is caused by the electrical charge traveling across the insulator (2) between the terminal post (1) and ground. Inspect for the following conditions: Inspect the spark plug boot for damage. Inspect the spark plug recess area of the cylinder head for moisture, such as oil, coolant, or water. A spark plug boot that is saturated causes arcing to ground.
3. Inspect the insulator (2) for cracks. All or part of the electrical charge may arc through the crack instead of the electrodes (3, 4).
4. Inspect for evidence of improper arcing. Measure the gap between the center electrode (4) and the side electrode (3) terminals. Refer to «Ignition System Specifications»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction__ignition-system-specifications) . An excessively wide electrode gap can prevent correct spark plug operation. Inspect for the correct spark plug torque. Refer to «Ignition System Specifications»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction__ignition-system-specifications) . Insufficient torque can prevent correct spark plug operation. An over-torqued spark plug causes the insulator (2) to crack. Inspect for signs of tracking that occurred near the insulator tip instead of the center electrode (4). Inspect for a broken or worn side electrode (3). Inspect for a broken, worn, or loose center electrode (4) by shaking the spark plug. A rattling sound indicates internal damage. A loose center electrode (4) reduces the spark intensity. Inspect for bridged electrodes (3, 4). Deposits on the electrodes (3, 4) reduce or eliminates the gap. Inspect for worn or missing platinum pads on the electrodes (3, 4), if equipped. Inspect for excess 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. Remove the ignition coil. Refer to «Ignition Coil(s) Replacement - Bank 1»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) and/or «Ignition Coil(s) Replacement - Bank 2»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
3. Use compressed air in order to remove debris from the spark plug cavity.
4. Remove the spark plug.

1. Ensure that the spark plug gap is equivalent to the spark plug gap specification. Refer to «Ignition System Specifications»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction__ignition-system-specifications) .
2. Install the spark plug. Tighten: Tighten the spark plug to 20 N.m (15 lb ft).
3. Install the ignition coil. Refer to «Ignition Coil(s) Replacement - Bank 1»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) and/or «Ignition Coil(s) Replacement - Bank 2»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .

1. Turn the ignition OFF.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Remove the catalytic converter. Refer to «Catalytic Converter Replacement»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
4. Disconnect the intermediate steering shaft from the steering gear. Refer to «Intermediate Steering Shaft Replacement»(/buick/rendezvous/i-2001-2007/remont/ignition-switchsteering-lock/#steering-wheel-steering-column) in Steering Wheel and Column.
5. Position a utility stand beneath the rear center section of the frame in order to support the powertrain.
6. Remove the frame rear bolts.
7. Carefully lower the powertrain in order to provide access.
8. Remove the crank sensor heat shield bolts (1, 2) and the heat shield.
9. Remove the crankshaft position (CKP) sensor bolt.
10. Use a long flat-bladed tool in order to carefully remove the CKP sensor and harness.
11. Disconnect the wiring harness from the CKP sensor.

1. Connect the CKP sensor wiring harness.
2. Use a long flexible pick-up tool in order to position the CKP sensor to the engine block.
3. Install the CKP sensor bolt. Tighten: Tighten the CKP sensor bolt to 10 N.m (89 lb in).
4. Install the crank sensor heat shield and the heat shield bolts. Tighten: Tighten the upper crank sensor heat shield bolt (1) to 10 N.m (89 lb in). Tighten the lower crank sensor heat shield bolt (2) to 50 N.m (37 lb in).
5. Raise the powertrain until the frame contacts the chassis.
6. Install the frame rear bolts. Refer to «Frame Replacement - Front (W/AWD)»(/buick/rendezvous/i-2001-2007/remont/frames-subframes-crossmembers/#frame-and-underbody) or «Frame Replacement - Front (W/FWD)»(/buick/rendezvous/i-2001-2007/remont/frames-subframes-crossmembers/#frame-and-underbody) in Frame and Underbody.
7. Connect the intermediate steering shaft to the steering gear. Refer to «Intermediate Steering Shaft Replacement»(/buick/rendezvous/i-2001-2007/remont/ignition-switchsteering-lock/#steering-wheel-steering-column) in Steering Wheel and Column.
8. Install the catalytic converter. Refer to «Catalytic Converter Replacement»(/buick/rendezvous/i-2001-2007/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
9. Lower the vehicle.

1. Turn the ignition OFF.
2. Remove the camshaft position (CMP) sensor electrical connector (2).
3. Disconnect the CMP sensor bolt.
4. Remove the CMP sensor.

1. Install the CMP sensor.
2. Install the CMP sensor bolt. Tighten: Tighten the CMP sensor bolt to 10 N.m (89 lb in).
3. Connect the CMP sensor electrical connector (2).

1. Turn the ignition OFF.
2. Disconnect the camshaft position (CMP) sensor electrical connector (1).
3. Remove the CMP sensor bolt.
4. Remove the CMP sensor.

1. Install the CMP sensor.
2. Install the CMP sensor bolt. Tighten: Tighten the CMP sensor bolt to 10 N.m (89 lb in).
3. Connect the CMP sensor electrical connector (1).

1. Turn the ignition OFF.
2. Remove the power steering pressure hose bracket nut and reposition as necessary, in order to gain access. Refer to «Power Steering Pressure Pipe/Hose Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) or «Power Steering Pressure Pipe/Hose Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.
3. Disconnect the camshaft position (CMP) sensor electrical connector (1).
4. Remove the CMP sensor bolt.
5. Remove the CMP sensor.

1. Install the CMP sensor.
2. Install the CMP sensor bolt. Tighten: Tighten the CMP sensor bolt to 10 N.m (89 lb in).
3. Connect the CMP sensor electrical connector (1).
4. Install the power steering pressure hose as necessary. Refer to «Power Steering Pressure Pipe/Hose Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) or «Power Steering Pressure Pipe/Hose Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.

1. Turn the ignition OFF.
2. Remove the power steering pressure hose bracket nut and reposition the hose as necessary in order to gain access. Refer to «Power Steering Pressure Pipe/Hose Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) or «Power Steering Pressure Pipe/Hose Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.
3. Disconnect the camshaft position (CMP) sensor electrical connector (2).
4. Remove the CMP sensor bolt.
5. Remove the CMP sensor.

1. Install the CMP sensor.
2. Install the CMP sensor bolt. Tighten: Tighten the CMP sensor bolt to 10 N.m (89 lb in).
3. Connect the CMP sensor electrical connector (2).
4. Install the power steering pressure hose bracket and nut as necessary. Refer to «Power Steering Pressure Pipe/Hose Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) or «Power Steering Pressure Pipe/Hose Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.

1. Turn the ignition OFF.
2. Remove the power steering pressure hose bracket and reposition the hose as necessary in order to gain access. Refer to «Power Steering Pressure Pipe/Hose Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) or «Power Steering Pressure Pipe/Hose Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.
3. Disconnect the camshaft position (CMP) actuator valve electrical connector (1).
4. Remove the CMP actuator valve bolt.
5. Remove the CMP actuator valve.

1. Install the CMP actuator valve.
2. Install the CMP actuator valve bolt. Tighten: Tighten the CMP actuator valve bolt to 10 N.m (89 lb in).
3. Connect the CMP actuator valve electrical connector (1).
4. Install the power steering pressure hose bracket and nut as necessary. Refer to «Power Steering Pressure Pipe/Hose Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) or «Power Steering Pressure Pipe/Hose Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.

1. Turn the ignition OFF.
2. Remove the power steering pressure hose bracket nut and reposition the hose as necessary in order to gain access. Refer to «Power Steering Pressure Pipe/Hose Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) or «Power Steering Pressure Pipe/Hose Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.
3. Disconnect the camshaft position (CMP) actuator valve electrical connector (2).
4. Remove the CMP actuator valve bolt.
5. Remove the CMP actuator valve.

1. Install the CMP actuator valve.
2. Install the CMP actuator valve bolt. Tighten: Tighten the CMP actuator valve bolt to 10 N.m (89 lb in).
3. Connect the CMP valve electrical connector (2).
4. Install the power steering pressure hose bracket and nut as necessary. Refer to «Power Steering Pressure Pipe/Hose Replacement (LA1)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) or «Power Steering Pressure Pipe/Hose Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.

1. Turn the ignition OFF.
2. Disconnect the camshaft position (CMP) actuator valve electrical connector (1).
3. Remove the CMP actuator valve bolt.
4. Remove the CMP actuator valve.

1. Install the CMP actuator valve.
2. Install the CMP actuator valve bolt. Tighten: Tighten the CMP actuator valve bolt to 10 N.m (89 lb in).
3. Connect the CMP actuator valve electrical connector (1).

1. Turn the ignition OFF.
2. Remove the power steering fluid reservoir bolts and reposition the power steering fluid reservoir in order to provide access. Refer to «Remote Power Steering Fluid Reservoir Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.
3. Disconnect the camshaft position (CMP) actuator valve electrical connector (2).
4. Remove the CMP actuator valve bolt.
5. Remove the CMP actuator valve.

1. Install the CMP actuator valve.
2. Install the CMP actuator valve bolt. Tighten: Tighten the CMP actuator valve bolt to 10 N.m (89 lb in).
3. Connect the CMP actuator valve electrical connector (2).

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Disconnect the intermediate steering shaft from the steering gear. Refer to «Intermediate Steering Shaft Replacement»(/buick/rendezvous/i-2001-2007/remont/ignition-switchsteering-lock/#steering-wheel-steering-column) in Steering Wheel and Column.
3. Position a utility stand beneath the rear center section of the frame in order to support the powertrain.
4. Remove the frame rear bolts.
5. Carefully lower the powertrain in order to provide access.
6. Remove the crank sensor heat shield bolts (1, 2) and the heat shield.
7. Disconnect the knock sensor (KS) electrical connector.
8. Remove the KS bolt and the KS.

1. Install the KS with the KS bolt.
2. Install the KS bolt. Tighten: Tighten the KS bolt to 23 N.m (17 lb ft).
3. Install the KS electrical connector.
4. Install the crank sensor heat shield and the heat shield bolts. Tighten: Tighten the upper crank sensor heat shield bolt (1) to 10 N.m (89 lb in). Tighten the lower crank sensor heat shield bolt (2) to 50 N.m (37 lb in).
5. Raise the powertrain until the frame contacts the chassis.
6. Install the frame rear bolts. Refer to «Frame Replacement - Front (W/AWD)»(/buick/rendezvous/i-2001-2007/remont/frames-subframes-crossmembers/#frame-and-underbody) or «Frame Replacement - Front (W/FWD)»(/buick/rendezvous/i-2001-2007/remont/frames-subframes-crossmembers/#frame-and-underbody) in Frame and Underbody.
7. Connect the intermediate steering shaft to the steering gear. Refer to «Intermediate Steering Shaft Replacement»(/buick/rendezvous/i-2001-2007/remont/ignition-switchsteering-lock/#steering-wheel-steering-column) in Steering Wheel and Column.
8. Lower the vehicle.

1. Turn the ignition OFF.
2. Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (LA1)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/rendezvous/i-2001-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Remove the knock sensor (KS) electrical connector bracket bolt (2) located near the oil filter (3).
5. Remove the KS bolt (1).
6. Disconnect the KS electrical connector.

1. Connect the KS electrical connector.
2. Install the KS and the knock sensor bolt. Tighten: Tighten the KS bolt to 23 N.m (17 lb ft).
3. Install the KS electrical connector bracket and the bracket bolt (2). Tighten: Tighten the KS electrical connector bracket bolt (2) to 65 N.m (48 lb ft).
4. Lower the vehicle.

1. Remove and reposition the power steering fluid reservoir to gain access. Refer to «Remote Power Steering Fluid Reservoir Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.
2. Disconnect the electrical connector to the control module for the intake manifold runner.
3. Remove the intake manifold runner control solenoid bolts.
4. Remove the intake manifold runner control solenoid.

1. Install the intake manifold runner control solenoid.
2. Install the intake manifold runner control solenoid bolts. Tighten: Tighten the intake manifold runner control solenoid bolts to 10 N.m (89 lb in).
3. Connect the electrical connector to the control module for the intake manifold runner.
4. Install the power steering fluid reservoir. Refer to «Remote Power Steering Fluid Reservoir Replacement (LY7)»(/buick/rendezvous/i-2001-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.

1. Remove the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction)
2. Remove the air cleaner side cover with the mass air flow (MAF) sensor.
3. Remove the filter element (1) from the air cleaner housing (2).

1. Install the filter element (1) into the air cleaner housing.
2. Install the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
3. Install the air cleaner side cover with the MAF sensor.

1. Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (LA1)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Remove the coolant reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) in Engine Cooling.
3. Remove the left front sheet metal diagonal brace. Refer to «Brace Replacement - Front Fender Upper Diagonal - Left»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
4. Remove the air inlet duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
5. Remove the air cleaner upper cover bolts and the upper cover.
6. Disconnect the mass air flow (MAF) sensor electrical connector.
7. Remove and reposition the TCM with the wiring harness in order to gain access.
8. Remove the air cleaner bolts and the air cleaner with the mass air flow sensor.

1. Install the air cleaner with the mass air flow sensor. Install the air cleaner bolts. Tighten: Tighten the air cleaner bolts to 10 N.m (89 lb in).
2. Install the TCM with the wiring harness to the air cleaner.
3. Connect the MAF sensor electrical connector.
4. Install the air cleaner upper cover and the upper cover bolts. Tighten: Tighten the air cleaner upper cover bolts to 2.3 N.m (20 lb in).
5. Install the air inlet duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-36l-ly7-introduction) .
6. Install the left front sheet metal diagonal brace. Refer to «Brace Replacement - Front Fender Upper Diagonal - Left»(/buick/rendezvous/i-2001-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
7. Install the coolant reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/buick/rendezvous/i-2001-2007/remont/cooling-fan/#engine-cooling-system) in Engine Cooling.
8. Connect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (LA1)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/rendezvous/i-2001-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.

1. Loosen the intake air duct clamps.
2. Disconnect the positive crankcase ventilation (PCV) tube from the air intake duct.
3. Remove the air intake duct from the throttle body and the mass air flow (MAF) sensor.
4. Remove the air intake duct.

1. Install the air intake duct to the MAF sensor.
2. Install the air cleaner intake duct to the throttle body.
3. Connect the PCV tube to the air intake duct.
4. Tighten the air intake air duct clamps. Tighten: Tighten the clamps to 2 N.m (18 lb in).

Scheme 30

The engine control module (ECM) (2) interacts with many emission related components and systems, and monitors the emission related components and systems for deterioration. OBD II diagnostics monitor the system performance and a diagnostic trouble code (DTC) sets if the system performance degrades.

The malfunction indicator lamp (MIL) operation and the DTC storage are dictated by the DTC type. A DTC is ranked as a Type A or Type B if the DTC is emissions related. Type C is a non-emissions related DTC.

The ECM is in the engine compartment. The ECM is the control center of the engine controls system. The ECM controls the following components

1. The fuel injection system
2. The ignition system
3. The emission control systems
4. The on-board diagnostics
5. The A/C and fan systems
6. The throttle actuation control (TAC) system

The ECM constantly monitors the information from various sensors and other inputs, and controls the systems that affect the vehicle performance and the emissions. The ECM also performs diagnostic tests on various parts of the system. The ECM can recognize operational problems and alert the driver via the MIL. When the ECM detects a malfunction, the ECM stores a DTC. The condition area is identified by the particular DTC that is set. This aids the technician in making repairs.

ECM Function

The engine control module (ECM) can supply 5 volts or 12 volts to the various sensors or switches. This is done through pull-up resistors to the regulated power supplies within the ECM. In some cases, even an ordinary shop voltmeter will not give an accurate reading because the resistance is too low. Therefore, a DMM with at least 10 megaohms input impedance is required in order to ensure accurate voltage readings.

The ECM controls the output circuits by controlling the ground or the power feed circuit through the transistors or a device called an output driver module.

EEPROM

The electronically erasable programmable read only memory (EEPROM) is a permanent memory that is physically part of the engine control module (ECM). The EEPROM contains program and calibration information that the ECM needs in order to control the powertrain operation.

Special equipment, as well as the correct program and calibration for the vehicle, are required in order to reprogram the ECM.

Theft Deterrent System Frequency Code Programming

This vehicle is equipped with a theft deterrent system which interfaces with the engine control module (ECM). If the ECM is replaced, program the new ECM with the frequency code of the theft deterrent module that is currently on the vehicle. The vehicle will not start until this procedure is completed.

KS Module

The engine control module (ECM) employs an internal integrated circuit to continuously monitor the knock control evaluation circuit. The knock sensor (KS) module contains the circuitry that allows the ECM to utilize the KS signals and diagnose the KS sensors and circuitry. If the ECM detects a fault in the ability of the KS module to sample these signals, a DTC sets.

Data Link Connector (DLC)

The data link connector (DLC) is a 16-pin connector that provides the technician a means of accessing serial data for aid in the diagnosis. This connector allows the technician to use a scan tool in order to monitor the various serial data parameters, and display the DTC information. The DLC is located inside of the drivers compartment, underneath the dash.

Malfunction Indicator Lamp (MIL)

The malfunction indicator lamp (MIL) is inside of the instrument panel cluster (IPC). The MIL is controlled by the engine control module (ECM) and illuminates when the ECM detects a condition that affects the vehicle emissions.

ECM Service Precautions

The engine control module (ECM), by design, can withstand the normal current draws that are associated with the vehicle operations. However, care must be used in order to avoid overloading any of these circuits. When testing for opens or shorts, do not ground or apply voltage to any of the ECM circuits unless the diagnostic procedure instructs you to do so. These circuits should only be tested with a DMM.

Emissions Diagnosis For State I/M Programs

This OBD II equipped vehicle is designed to diagnose any conditions that could lead to excessive levels of the following emissions

1. Hydrocarbons (HC)
2. Carbon monoxide (CO)
3. Oxides of nitrogen (NOx)
4. Evaporative emission (EVAP) system losses

Should this vehicles on-board diagnostic system (ECM) detect a condition that could result in excessive emissions, the ECM turns ON the malfunction indicator lamp (MIL) and stores a DTC that is associated with the condition.

Aftermarket (Add-On) Electrical And Vacuum Equipment

Note. Do not attach add-on vacuum operated equipment to this vehicle. The use of add-on vacuum equipment may result in damage to vehicle components or systems.

Note. Connect any add-on electrically operated equipment to the vehicle's electrical system at the battery (power and ground) in order to prevent damage to the vehicle.

Aftermarket, add-on, electrical and vacuum equipment is defined as any equipment installed on a vehicle after leaving the factory that connects to the vehicles electrical or vacuum systems. No allowances have been made in the vehicle design for this type of equipment.

Add-on electrical equipment, even when installed to these strict guidelines, may still cause the powertrain system to malfunction. This may also include equipment not connected to the vehicle electrical system, such as portable telephones and radios. Therefore, the first step in diagnosing any powertrain condition is to eliminate all of the aftermarket electrical equipment from the vehicle. After this is done, if the problem still exists, the problem may be diagnosed in the normal manner.

Electrostatic Discharge (ESD) Damage

The electronic components that are used in the control systems are often designed to carry very low voltage. The electronic components are susceptible to damage caused by electrostatic discharge. Less than 100 volts of static electricity can cause damage to some electronic components. By comparison, it takes as much as 4,000 volts for a person to even feel the zap of a static discharge.

There are several ways for a person to become statically charged. The most common methods of charging are by friction and by induction. An example of charging by friction is a person sliding across a car seat.

Charging by induction occurs when a person with well insulated shoes stands near a highly charged object and momentarily touches ground. Charges of the same polarity are drained off leaving the person highly charged with the opposite polarity. Static charges can cause damage, therefore, it is important to use care when handling and testing electronic components.

Emissions Control Information Label

The underhood Vehicle Emissions Control Information Label contains important emission specifications and setting procedures. In the upper left corner is the exhaust emission information. This identifies the year, the manufacturing division of the engine, the displacement of the engine in liters, the class of the vehicle, and type of fuel metering system. There is also an illustrated emission components and vacuum hose schematic.

This label is located in the engine compartment of every General Motors vehicle. If the label has been removed, it can be ordered from GM service parts operations (GMSPO).

Underhood Inspection

Perform a careful underhood inspection when performing any diagnostic procedure or diagnosing the cause of an emission test failure. This can often lead to repairing a condition without further steps. Use the following guidelines when performing an inspection

1. Inspect all of the vacuum hoses for correct routing, pinches, cuts, or disconnects.
2. Inspect any hoses that are difficult to see.
3. Inspect all of the wires in the engine compartment for the following conditions: Burned or chafed spots Pinched wires Contact with sharp edges Contact with hot exhaust manifolds

Basic Knowledge Required

Note. Lack of basic knowledge of this powertrain when performing diagnostic procedures could result in incorrect diagnostic performance or damage to powertrain components. Do not attempt to diagnose a powertrain problem without this basic knowledge.

A basic understanding of hand tools is necessary in order to effectively use this section of the Service Manual.

You must be familiar with some of the basics of engine operation and electrical diagnosis in order to use this section of the service manual.

1. Basic electrical circuits-You should have an understanding of basic electricity and know the meaning of voltage (volts), current (amps), and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire, and you should be able to identify a shorted or open circuit by using a DMM. You should be able to read and understand a wiring diagram.
2. Use of digital multimeter-You should be familiar with the DMM, particularly the essential tool. You should be able to use the meter in order to measure the voltage (volts), the resistance (ohms), the current (amps), intermittents (min/max), and frequency (Hertz).
3. Use of circuit testing tools-You should not use a test lamp to diagnose the engine controls system unless you are specifically instructed to do so. You should know how to the use jumper wires in order to test the components and allow the DMM readings without damaging the terminals. You should know how to use the J 35616 connector test adapter kit and use the kit whenever the diagnostic procedures call for front probing any connector.

Throttle Actuator Control (TAC) System Description

The throttle actuator control (TAC) system is used to improve emissions, fuel economy, and driveability. The TAC system eliminates the mechanical link between the accelerator pedal and the throttle plate. The TAC system eliminates the need for a cruise control module and idle air control motor. The following is a list of TAC system components

1. The accelerator pedal assembly includes the following components: The accelerator pedal The accelerator pedal position (APP) sensor 1 The APP sensor 2
2. The throttle body assembly includes the following components: The throttle position (TP) sensor 1 The TP sensor 2 The throttle actuator motor The throttle plate
3. The engine control module (ECM)

The ECM monitors the driver's demand for acceleration with 2 APP sensors. The APP sensor 1 signal voltage range is from about 0.98-4.16 volts as the accelerator pedal is moved from the rest pedal position to the full pedal travel position. The APP sensor 2 range is from about 0.49-2.08 volts as the accelerator pedal is moved from the rest pedal position to the full pedal travel position. The ECM processes this information along with other sensor inputs to command the throttle plate to a certain position.

The throttle plate is controlled with a direct current motor called a throttle actuator control motor. The ECM can move this motor in the forward or reverse direction by controlling battery voltage and/or ground to 2 internal drivers. The throttle plate is held at a 7 percent rest position using a constant force return spring. This spring holds the throttle plate to the rest position when there is no current flowing to the actuator motor.

The ECM monitors the throttle plate angle with 2 TP sensors. The TP sensor 1 signal voltage range is from about 0.50-4.25 volts as the throttle plate is moved from 0 percent to wide open throttle (WOT). The TP sensor 2 voltage range is from about 4.45-0.70 volts as the throttle plate is moved from 0 percent to WOT.

The ECM performs diagnostics that monitor the voltage levels of both APP sensors, both TP sensors, and the throttle actuator control motor circuit. It also monitors the spring return rate of both return springs that are housed internal to the throttle body assembly. These diagnostics are performed at different times based on whether the engine is running, not running, or whether the ECM is currently in a throttle body relearn procedure.

Every ignition cycle, the ECM performs a quick throttle return spring test to make sure the throttle plate can return to the 7 percent rest position from the 0 percent position. This is to ensure that the throttle plate can be brought to the rest position in case of an actuator motor circuit failure. Observe, under cold conditions, the ECM commands the throttle plate to 7 percent with the ignition ON and the engine OFF to release any ice that may have formed on the throttle plate.

Throttle Body Relearn Procedure

The ECM stores values that include the lowest possible TP sensor positions-0 percent, the rest positions-7 percent, and the return rate of both springs. These values will only be erased or overwritten if the ECM is reprogrammed or if a throttle body relearn procedure is performed. Observe, if the battery is disconnected, the ECM will immediately perform a throttle body relearn procedure when the ignition is turned ON.

A throttle body relearn procedure is performed anytime the ignition is turned ON, with the engine OFF for longer than 29 seconds when the following conditions have been met

1. The engine speed is less than 40 RPM.
2. The vehicle speed is 0 km/h (0 mph).
3. The engine coolant temperature (ECT) is between 5-60°C (41-140°F).
4. The intake air temperature (IAT) is more than 5-60°C (41-140°F).
5. The APP sensor angle is less than 14.9 percent.
6. The ignition 1 voltage is more than 10 volts.

After 29 seconds, the ECM commands the throttle plate from the rest position to full closed, then to around 10 percent open. This procedure takes about 6-8 seconds. If any faults occur in the TAC system, a DTC sets. At the start of this procedure, the Scan tool TAC Learn Counter parameter should display 0, then count up to 11 after the procedure is completed. If the counter did not start at 0, or if the counter did not end at 11, a fault has occurred and a DTC should set.

TAC System Default Actions/Reduce Power Modes

There are 2 reduce power modes that the ECM can default to if an error is detected in the TAC system. If an APP sensor 1 or APP sensor 2 circuit fault, TP sensor 2 circuit fault or if a TP sensor 1 circuit fault is detected with some APP angle, the ECM goes into one of the 2 reduce power modes. In this mode, the engine torque is limited so that the vehicle cannot reach speeds of more than 100 km/h (60 mph). The ECM remains in this reduce power mode during the entire ignition cycle even if the fault is corrected.

If there is a condition with the throttle actuator control circuits, throttle actuator command vs actual position fault, return spring check fault, or a TP sensor 1 circuit fault, the ECM goes into the other reduce engine power mode. In this mode, the engine speed is limited to 2,500 RPM and the 3-6 fuel injectors are randomly turned OFF. At this time the Reduced Power indicator is commanded ON. The ECM remains in the reduce power mode during the entire ignition cycle even if the fault is corrected. Observe, if a TP sensor 1 or throttle actuator control circuit fault is present at the time the vehicle is at idle, with no accelerator pedal angle, the engine may stall.

Scheme 31

The camshaft actuator system enables the engine control module (ECM) to change camshaft timing of all 4 camshafts while the engine is operating. The CMP actuator assembly (15) varies the camshaft position in response to directional changes in oil pressure. The CMP actuator solenoid valve controls the oil pressure that is applied to advance or retard a camshaft. Modifying camshaft timing under changing engine demand provides better balance between the following performance concerns

1. Engine power output
2. Fuel economy
3. Lower tailpipe emissions

The CMP actuator solenoid valve (7) is controlled by the ECM. The crankshaft position (CKP) sensor and the CMP sensors are used to monitor changes in camshaft positions. The ECM uses the following information in order to calculate the desired camshaft positions

1. The engine coolant temperature (ECT) sensor
2. The calculated engine oil temperature (EOT)
3. The mass air flow (MAF) sensor
4. The throttle position (TP) sensor
5. The vehicle speed sensor (VSS)
6. The volumetric efficiency

Operation

The CMP actuator assembly has an outer housing that is driven by an engine timing chain. Inside the assembly is a rotor with fixed vanes that is attached to the camshaft. Oil pressure that is applied to the fixed vanes will rotate a specific camshaft in relationship to the crankshaft. The movement of the intake camshafts will advance the intake valve timing up to a maximum of 50 crankshaft degrees. The movement of the exhaust camshafts will retard the exhaust valve timing up to a maximum of 50 crankshaft degrees. When oil pressure is applied to the return side of the vanes, the camshafts will return to 0 crankshaft degrees, or top dead center (TDC). The CMP actuator solenoid valve directs the oil flow that controls the camshaft movement. The ECM commands the CMP solenoid to move the solenoid plunger and spool valve until oil flows from the advance passage (11). Oil flowing thru the CMP actuator assembly from the CMP solenoid advance passage applies pressure to the advance side of the vanes in the CMP actuator assembly. When the camshaft position is retarded, the CMP actuator solenoid valve directs oil to flow into the CMP actuator assembly from the retard passage (3). The ECM can also command the CMP actuator solenoid valve to stop oil flow from both passages in order to hold the current camshaft position.

The ECM operates the CMP actuator solenoid valve by pulse width modulation (PWM) of the solenoid coil. The higher the PWM duty cycle, the larger the change in camshaft timing. The CMP actuator assembly also contains a lock pin (14) that prevents movement between the outer housing and the rotor vane assembly. The lock pin is released by oil pressure before any movement in the CMP actuator assembly takes place. The ECM is continuously comparing CMP sensor inputs with CKP sensor input in order to monitor camshaft position and detect any system malfunctions. If a condition exists in either the intake or exhaust camshaft actuator system, the opposite bank, intake or exhaust, camshaft actuator will default to 0 crankshaft degrees.

CMP Actuator System Operation

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 32

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

Scheme 33

Note. Use a fuel tank filler pipe cap with the same features as the original when a replacement is necessary. Failure to use the correct fuel tank filler pipe cap can result in a serious malfunction of the fuel system.

The fuel tank filler pipe is equipped with a turn to vent screw on the type cap which incorporates a ratchet action in order to prevent over-tightening.

The turn to vent feature allows the fuel tank pressure relief prior to removal. Instructions for proper use are imprinted on the cap cover. A vacuum safety relief valve is incorporated into this cap.

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 34

Scheme 35

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 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 Sender Strainers

The strainers act as a coarse filter to perform the following functions

1. Filter contaminants
2. Separate water from fuel
3. Provide a wicking action that helps draw fuel into the fuel pump

Fuel stoppage at the strainer indicates that the fuel tank contains an abnormal amount of sediment or water. Therefore, the fuel tank will need to be removed and cleaned, and the filter strainer should be replaced.

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 36

The fuel pressure regulator (2) is contained in the fuel sender assembly. The fuel pressure regulator is a diaphragm relief valve. The diaphragm has fuel pressure on one side and regulator spring pressure on the other side. 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.

On-Board Refueling Vapor Recovery (ORVR) System

The on-board refueling vapor recovery (ORVR) system is an on-board vehicle system to recover fuel vapors during the vehicle refueling operation. The flow of liquid fuel down to the fuel tank filler neck provides a liquid seal. The purpose of ORVR is to prevent refueling vapor from exiting the fuel tank filler neck. The ORVR components are listed below, with a brief description of their operation

1. The fuel tank-The fuel tank contains the modular fuel sender, the fuel limiter vent valve (FLVV), and 1 rollover valve.
2. The fuel filler pipe-The fuel filler pipe carries fuel from the fuel nozzle to the fuel tank.
3. The evaporative emission (EVAP) canister-The EVAP canister receives refueling vapor from the fuel system, stores the vapor, and releases the vapor to the engine upon demand.
4. The vapor lines-The vapor lines transport fuel vapor from the tank assembly to the EVAP canister and engine.
5. The check valve-The check valve limits fuel spit-back from the fuel tank during the refueling operation by allowing fuel flow only into the fuel tank. The check valve is located at the bottom of the fuel filler pipe.
6. The modular fuel sender assembly-The modular fuel sender assembly pumps fuel to the engine from the fuel tank.
7. The fuel tank pressure (FTP) sensor is located on top of the fuel tank vapor dome.
8. The FLVV-The FLVV acts as a shut-off valve. The FLVV is located in the fuel tank. This valve has the following functions: Controlling the fuel tank fill level by closing the primary vent from the fuel tank Preventing fuel from exiting the fuel tank via the vapor line to the canister Providing fuel spillage protection in the event of a vehicle rollover by closing the vapor path from the tank to the engine
9. The pressure vacuum relief valve-The pressure vacuum relief valve provides venting of excessive fuel tank pressure and vacuum. The valve is located in the fuel fill cap.
10. The vapor recirculation line-The vapor recirculation line is used to transport vapor from the fuel tank to the top of the fill pipe during refueling to reduce vapor loading to the enhanced EVAP canister.

Fuel Feed Pipes

The fuel feed pipe carries fuel from the fuel tank to the fuel injection system.

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.

Fuel Rail

The fuel rail consists of 3 parts

1. The pipe that carries fuel to each injector
2. The fuel pressure test port
3. Six individual fuel injectors

The fuel rail is mounted on the intake manifold and distributes the fuel to each cylinder through the individual injectors.

Fuel Injectors

The fuel injector is a solenoid device that is controlled by the engine control module (ECM). When the ECM energizes the injector coil, a normally closed ball valve opens, allowing the fuel to flow past a director plate to the injector outlet. The director plate has holes that control the fuel flow, generating a dual conical spray pattern of finely atomized fuel at the injector outlet. The fuel from the outlet is directed at both of the intake valves, causing the fuel to become further vaporized before entering the combustion chamber.

The fuel injectors will cause various driveability conditions if the following conditions occur

1. If the injectors will not open
2. If the injectors are stuck open
3. If the injectors are leaking
4. If the injectors have a low coil resistance

Fuel Pump Relay

The fuel pump relay allows the engine control module (ECM) to energize the fuel pump. The ECM enables the fuel pump whenever the crankshaft position (CKP) sensor pulses are detected.

Engine Fueling

The engine is fueled by six individual injectors, one for each cylinder, that are controlled by the engine control module (ECM). The ECM controls each injector by energizing the injector coil for a brief period once every other engine revolution. The length of this brief period, or pulse, is carefully calculated by the ECM to deliver the correct amount of fuel for proper driveability and emissions control. The period of time when the injector is energized is called the pulse width and is measured in milliseconds, thousandths of a second.

While the engine is running, the ECM is constantly monitoring the inputs and recalculating the appropriate pulse width for each injector. The pulse width calculation is based on the injector flow rate, mass of fuel the energized injector will pass per unit of time, the desired air/fuel ratio, and actual air mass in each cylinder and is adjusted for battery voltage, short term, and long term fuel trim. The calculated pulse is timed to occur as each cylinders intake valves are closing to attain largest duration and most vaporization.

Fueling during a crank is slightly different than fueling during an engine run. As the engine begins to turn, a prime pulse may be injected to speed starting. As soon as the ECM can determine where in the firing order the engine is, the ECM begins pulsing the injectors. The pulse width during the crank is based on the coolant temperature and the engine load.

The fueling system has several automatic adjustments in order to compensate for the differences in the fuel system hardware, the driving conditions, the fuel used, and the vehicle aging. The basis for the fuel control is the pulse width calculation that is described above. Included in this calculation are an adjustment for the battery voltage, the short term fuel trim, and the long term fuel trim. The battery voltage adjustment is necessary since the changes in the voltage across the injector affect the injector flow rate. The short term and the long term fuel trims are fine and gross adjustments to the pulse width that are designed in order to maximize the driveability and emissions control. These fuel trims are based on the feedback from the oxygen sensors in the exhaust stream and are only used when the fuel control system is in a Closed Loop operation.

Under certain conditions, the fueling system will turn OFF the injectors for a period of time. This is referred to as fuel shut-off. Fuel shut-off is used in order to improve traction, save fuel, improve emissions, and protect the vehicle under certain extreme or abusive conditions.

In case of a major internal problem, the ECM may be able to use a back-up fuel strategy for limp in mode that will run the engine until service can be performed.

Sequential Fuel Injection (SFI)

The engine control module (ECM) controls the fuel injectors based on information that the ECM receives from several information sensors. Each injector is fired individually in the engine firing order, which is called sequential fuel injection. This allows precise fuel metering to each cylinder and improves the driveability under all of the driving conditions.

The ECM has several operating modes for fuel control, depending on the information that has been received from the sensors.

Starting Mode

When the engine control module (ECM) detects reference pulses from the crankshaft position (CKP) sensor, the ECM will enable the fuel pump. The fuel pump runs and builds up pressure in the fuel system. The ECM then monitors the mass air flow (MAF), intake air temperature (IAT), engine coolant temperature (ECT), and the throttle position (TP) sensor signal in order to determine the required injector pulse width for starting.

Clear Flood Mode

If the engine is flooded with fuel during starting and will not start, the Clear Flood Mode can be manually selected. To select Clear Flood Mode, push the accelerator to wide open throttle (WOT). With this signal, the engine control module (ECM) will completely turn OFF the injectors and will maintain this stage as long as the ECM indicates a WOT condition with engine speed below a predetermined value.

Run Mode

The Run Mode has 2 conditions: Open Loop operation and Closed Loop operation. When the engine is first started and the engine speed is more than a predetermined value, the system goes into Open Loop operation. In Open Loop operation, the engine control module (ECM) ignores the signals from the oxygen sensors and calculates the required injector pulse width based primarily on inputs from the mass air flow (MAF), intake air temperature (IAT) and engine coolant temperatures (ECT) sensors.

In Closed Loop, the ECM adjusts the calculated injector pulse width for each bank of injectors based on the signals from each oxygen sensor.

Acceleration Mode

The engine control module (ECM) monitors the changes in the throttle position (TP) and the mass air flow (MAF) sensor signals in order to determine when the vehicle is being accelerated. The ECM will then increase the injector pulse width in order to provide more fuel for improved performance.

Deceleration Mode

The engine control module (ECM) monitors changes in throttle position (TP) and mass air flow (MAF) sensor signals to determine when the vehicle is being decelerated. The ECM will then decrease injector pulse width or even shut OFF injectors for short periods to reduce exhaust emissions, and for better (engine braking) deceleration.

Battery Voltage Correction Mode

The engine control module (ECM) can compensate in order to maintain acceptable vehicle driveability when the ECM sees a low battery voltage condition. The ECM compensates by performing the following functions

1. Increasing the injector pulse width in order to maintain the proper amount of fuel being delivered
2. Increasing the idle speed to increase the generator output

Fuel Shut-Off Mode

The engine control module (ECM) has the ability to completely turn OFF all of the injectors or selectively turn OFF some of the injectors when certain conditions are met. These fuel shut-off modes allow the ECM to protect the engine from damage and also to improve the vehicles driveability.

The ECM will disable all of the six injectors under the following conditions

1. Ignition OFF-Prevents engine run-on
2. Ignition ON but no crank position (CKP) signal-Prevents flooding or backfiring
3. A high engine speed-Above the red line
4. A high vehicle speed-Above the rated tire speed
5. Closed throttle cast down-Reduces the emissions and increases engine braking.

The ECM will selectively disable the injectors under the following conditions

1. The torque management enabled-Transmission shifts or abusive maneuvers.
2. The traction control enabled-In conjunction with the front brakes applying

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 valve to 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 valve ON, open, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent valve OFF, open, fresh air will be drawn through the valve and 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 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 EVAP system. The control module will command the EVAP vent valve ON, closed, and command the EVAP purge valve ON, open, 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 valve OFF, closed, 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 sets.

Small Leak Test

The engine off natural vacuum, (EONV), diagnostic is the small leak detection diagnostic for the EVAP system. The EONV diagnostic monitors the EVAP system pressure or vacuum with the key OFF. The EONV utilizes the temperature changes and the resulting naturally occurring vacuum or pressure in the fuel tank immediately following a drive cycle. When the vehicle is driven, the temperature in the fuel tank rises. When the vehicle is parked with the engine OFF and key OFF, the temperature in the fuel tank will continue to rise for a period of time, and then begin to decrease. The EONV diagnostic relies on this temperature change, and the 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 (0.020 in). The diagnostic can determine if a small leak is present based on vacuum or pressure readings in the EVAP system. When the EVAP system is sealed a finite amount of pressure or vacuum will be observed. When a 0.51 mm (0.020 in) leak is present, 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 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 valve ON, open; and commanding the EVAP vent valve OFF, open; and monitoring the FTP sensor for an increase in vacuum. If vacuum increases more than a calibrated value, DTC P0446 sets.

Purge Valve Leak Test

If the EVAP purge 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 valve OFF, closed; and vent valve ON, closed; sealing the system, and monitoring the FTP for an increase in vacuum. If the control module detects that EVAP system vacuum increases above a calibrated value, DTC P0496 sets.

EVAP System Components

The 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 Valve

The EVAP purge valve controls the flow of vapors from the EVAP system to the intake manifold. 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 Valve

The EVAP vent valve controls fresh airflow into the EVAP canister. The valve is normally open. The control module will command the valve closed during some EVAP tests, allowing the system to be tested for leaks.

Fuel Tank Pressure Sensor

The 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. As FTP increases, FTP sensor voltage decreases, high pressure = low voltage. As FTP decreases, FTP voltage increases, low pressure or vacuum = high voltage.

EVAP Service Port

The EVAP service port is located in the EVAP purge pipe between the EVAP purge 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 an individual coil for each cylinder. The ignition coils are mounted in the center of each camshaft cover with short integrated boots connecting the coils to the spark plugs. The driver modules within each ignition coil are commanded ON/OFF by the engine control module (ECM). The ECM primarily uses engine speed, the MAF sensor signal, and position information from the crankshaft position (CKP) and the camshaft position (CMP) sensors. This controls the sequence, dwell, and timing of the spark. The EI system consists of the following components

Crankshaft Position (CKP) Sensor

The crankshaft position (CKP) sensor works in conjunction with a 58 tooth reluctor wheel on the crankshaft. The engine control module (ECM) monitors the voltage between the CKP sensor signal circuits. As each reluctor wheel tooth rotates past the sensor, the sensor creates an analog signal. This analog signal is processed by the ECM. The reluctor wheel teeth are 6 degrees apart. Having only 58 teeth leaves a 12 degree span that is uncut. This creates a signature pattern that enables the ECM to determine the CKP. The ECM can determine which pair of cylinders is approaching top dead center based on the CKP signal alone. The camshaft position (CMP) sensor signals are used in order to determine which of these 2 cylinders is on a firing stroke, and which is on the exhaust stroke. The ECM uses this to properly synchronize the ignition system, the fuel injectors, and the knock control. This sensor is also used in order to detect misfire.

Camshaft Position (CMP) Sensor

This engine uses 4 camshaft position (CMP) sensors, one for each camshaft. The CMP sensor signals are a digital ON/OFF pulse, output 4 times per revolution of the camshaft. The CMP sensor does not directly affect the operation of the ignition system. The CMP sensor information is used by the engine control module (ECM) to determine the position of the 4 camshafts relative to the crankshaft position. By monitoring the CMP and crankshaft position (CKP) signals the ECM can accurately time the operation of the fuel injectors. The ECM supplies the CMP sensor with a 5-volt reference circuit and a low reference circuit. The CMP sensor signals are an input to the ECM. These signals are also used to detect camshaft alignment with the crankshaft.

Ignition Coils

Each ignition coil contains a solid state driver module as its primary element. The engine control module (ECM) signals the coil driver to initiate a firing event by applying ignition control (IC) circuit current for the appropriate time, or dwell. When the current is removed the coil fires the spark plug. The ignition coils use the following circuits

1. An ignition 1 voltage supply circuit
2. An IC circuit
3. Two ground circuits

Engine Control Module (ECM)

The engine control module (ECM) controls all ignition system functions, and constantly corrects the spark timing. The ECM monitors information from various sensor inputs that include the following components

1. The throttle position (TP) sensor
2. The engine coolant temperature (ECT) sensor
3. The mass air flow (MAF) sensor
4. The intake air temperature (IAT) sensor
5. The vehicle speed sensor (VSS)
6. The transmission gear position or range information sensors
7. The engine knock sensors (KS)
8. Ambient pressure sensor (BARO)

Knock Sensor (KS) System Description

You can diagnose all of the sensors and most of the input circuits with a scan tool. Within this section is a short description of how to use a scan tool wherever possible to diagnose these circuits. You can also use the scan tool to compare the values for an engine that is running normally with the engine you are diagnosing.

The knock sensor (KS) system detects engine knocking or pinging. The ECM will retard the spark timing based on the signals from the KS system. The KS produce an AC voltage that is sent to the engine control module (ECM). The amount of the AC voltage produced is proportional to the amount of knock.

The ECM monitors the voltage of the sensors after each cylinder has fired.

If knock occurs in any of the cylinders, the ignition will be retarded for that particular cylinder. If the knocking then stops, the ignition will be restored to what it was before in steps.

Should knocking continue in the same cylinder in spite of the ignition being retarded, the ECM will retard the ignition an additional steps, and so on, up to a maximum of 12 degrees of retard. The ignition will also be retarded at high ambient temperatures in order to counteract knocking tendencies provoked by high intake air temperatures.

Should either bank 1 or bank 2 sensor fail to work, or should an internal circuit problem occur, the ignition timing will then use a default strategy. The default strategy will retard the ignition the maximum allowed amount to protect the engine from possible damage.

Scheme 37

The MAF sensor measures the amount of air coming into the engine. This direct airflow measurement is more accurate than the calculated airflow information obtained from the other sensor inputs. The MAF sensor also houses an integrated intake air temperature (IAT) sensor. The MAF sensor uses the following circuits

1. An ignition 1 voltage circuit
2. A 5-volt reference circuit
3. A low reference circuit
4. A signal circuit
5. IAT signal circuit

The MAF sensor that is used on this vehicle is a hot film type and is used in order to measure the air flow rate. The MAF output voltage is a function of the power required to keep the air flow sensing elements at a fixed temperature above the ambient temperature. The air flowing through the sensor cools the sensing elements. The amount of cooling is proportional to the amount of air flow. As the air flow increases, more current is needed in order to maintain the hot film at a constant temperature. The MAF sensor converts the changes in the current draw to a voltage signal that the ECM monitors. The ECM calculates the air flow based on this signal.

The ECM monitors the MAF sensor signal voltage and can determine if the sensor signal voltage is too low or too high. The ECM can also detect airflow that is inappropriate for a given operating condition based on the signal voltage.

The scan tool displays the MAF value and displays the value in grams per second (g/s). Values should change rather quickly on acceleration, but should remain fairly stable at any given engine speed. If the ECM detects a condition with the MAF sensor circuits, the following DTCs set

1. P0101 Mass Air Flow (MAF) Sensor Performance
2. P0102 Mass Air Flow (MAF) Sensor Circuit Low Voltage
3. P0103 Mass Air Flow (MAF) Sensor Circuit High Voltage

Scheme 38

The characteristic torque curve of a normally aspirated engine depends mainly on how the engines average pressure changes over the engine speed band. The average pressure is proportional to the volume of the air mass present in the cylinder when the inlet valve is closed. The design of the inlet system determines how large an air mass can be drawn into a cylinder at a given engine speed.

An intake manifold runner control (IMRC) valve (2) is used to change the intake manifold runner configuration. When the IMRC valve is open, the intake manifold is configured to one large plenum (4). When the IMRC valve is closed, the intake manifold is configured to two smaller plenums (3). The two intake manifold runner sizes result in different torque curves which improves performance at low and high engine speeds. The IMRC valve is located in the intake manifold (1). The ignition voltage circuit and the IMRC control circuit are routed to the IMRC solenoid thru an IMRC driver module. The IMRC driver module is an amplifier that is used to strengthen the IMRC solenoids ability to remain in the position commanded by the engine control module (ECM), during high load and current demands.

Special Tools

Special Tools Illustration Tool Number/Description EL 39021-460 Injector Harness Adapter J 23738-A Vacuum Pump J 26792 Spark Tester J 34730-1A Fuel Pressure Gage J 34730-405 Injector Test Lamp J 35616-B Connector Test Adapter Kit J 35616-200 Un-powered Test Light Kit J 36850 Transjel Lubricant J 37088-A Fuel Line Disconnect Tool Set J 37287 Inlet and Return Fuel Line Shut-Off Adapters J 37287-100 Fuel Line Shut-Off Quick Connect Adapters J 39021 Fuel Injector Coil/Balance Test J 39021-210 Injector Switch Box J 39200 Digital Multimeter (DMM) J 41413-200 Evaporative Emission System Tester (EEST) J 41413-300 EVAP Cap and Plug Kit J 41413-SPT High Intensity White Light J 41413-VLV Evaporative Emission Service Port Fitting J 41415-40 Fuel Tank Cap Adapter J 42598-B CAN+ Vehicle Data Recorder J 42960-02 Fuel Flap Door Holder J 44175 Fuel Composition Tester J 44602 Injector Test Adapter J 45004 Fuel Tank Drain Hose J 45289 Controller Area Network Diagnostic Interface (CANdi) Module J 45722 Fuel Sender Lock Ring Wrench 70000081 Tech II Scan Tool

Scheme 39

Scheme 40

Scheme 41

Scheme 42

Scheme 43

Scheme 44

Scheme 45

Scheme 46

Scheme 47

Scheme 48

Scheme 49

Scheme 50

Scheme 51

Scheme 52

Scheme 53

Scheme 54

Scheme 55

Scheme 56

Scheme 57

Scheme 58

Scheme 59

Scheme 60

Scheme 61

See also:
• Electrical Center Identification Views
• Battery Negative Cable Disconnect/Connect Procedure (LA1)
• Fastener Notice
• Service Programming System (SPS)
• Draining and Filling Cooling System
• Lifting and Jacking the Vehicle
• Intermediate Steering Shaft Replacement
• Front Fender Liner Replacement
• Frame Replacement - Front (W/AWD)
• Closeout/Insulator Panel Replacement - Left
• Gasoline/Gasoline Vapors Caution
• Fuel Tank Draining Procedure
• Fuel Pressure Relief Procedure
• Intake Manifold Replacement - Upper
• Safety Glasses and Compressed Air Caution
• Catalytic Converter Replacement
• Power Steering Pressure Pipe/Hose Replacement (LA1)
• Idle Learn Procedure
• Air Cleaner Intake Duct Replacement
• Fuel Pressure Relief Procedure
• Ignition System Specifications