Engine Controls - 2.6l & 3.2l - Introduction Cadillac CTS 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.

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

1. The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC Last Test Failed clears when the diagnostic runs and passes.
3. Use a scan tool in order to clear the MIL and the DTC.

Non-Emissions Related DTCs

Action Taken When the DTC Sets - Type C

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The MIL will not illuminate.
3. The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC - Type C

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

Conditions for Clearing the DTC - Type X

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

Diagnostic Trouble Code (DTC) Type(s)

Diagnostic Trouble Code (DTC) Type(s)

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Engine Controls Schematic Icons

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

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Engine Control Module (ECM) Connector End Views

Engine Control Module (ECM) Connector End C1 Connector Part Information 1928403379 64-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1 YE 581 TAC Motor Control - 1 2 YE 5036 HO2S Heater Low Control - Bank 2 Sensor 2 3 PK/BK 1746 Fuel Injector 3 Control 4 L-BU/WH 5041 IMRC Solenoid Control 5 D-GN/WH 428 EVAP Canister Purge Solenoid Control 6 TN 407 Low Reference 7 TN 1671 HO2S Low Signal - Bank 2 Sensor 2 8 BN/WH 633 CMP Sensor Signal 9 - - Not Used 10 WH/BK 5039 CKP Sensor High 11 - - Not Used 12 TN 1667 HO2S Low Signal - Bank 2 Sensor 1 13 - - Not Used 14 D-GN 2125 IC 5 Control 15 L-BU 2123 IC 3 Control 16 PU 2121 IC 1 Control 17 BN 582 TAC Motor Control - 2 18 PU/WH 5037 HO2S Heater Low Control - Bank 2 Sensor 1 19 TN 1744 Fuel Injector 1 Control 20 TN/WH 845 Fuel Injector 5 Control 21 - - Not Used 22 D-BU 496 Knock Sensor 1 Signal 23 PU/WH 1668 HO2S High Signal - Bank 1 Sensor 2 24 D-GN 485 TP Sensor 1 Signal 25 YE 410 ECT Sensor Signal 26 TN 2761 Low Reference 27 - - Not Used 28 PU/WH 1665 HO2S High Signal - Bank 1 Sensor 1 29 TN/BK 231 Oil Pressure Switch Signal 30 OG/WH 2122 IC 2 Control 31 D-GN/WH 2124 IC 4 Control 32 L-BU/WH 2126 IC 6 Control 33 YE 581 TAC Motor Control - 1 34 PU 5035 HO2S Heater Low Control - Bank 1 Sensor 2 35 L-GN/BK 1745 Fuel Injector 2 Control 36 YE/BK 846 Fuel Injector 6 Control 37 - - Not Used 38 L-BU 1876 Knock Sensor 2 Signal 39 PU 1670 HO2S High Signal - Bank 2 Sensor 2 40 PU 486 TP Sensor 2 Signal 41 - - Not Used 42 TN 2752 Low Reference 43 - - Not Used 44 PU 1666 HO2S High Signal - Bank 2 Sensor 1 45-48 - - Not Used 49 BN 582 TAC Motor Control - 2 50 L-BU 5038 HO2S Heater Low Control - Bank 1 Sensor 1 51 TN 2760 5-Volt Reference 52 L-BU/BK 844 Fuel Injector 4 Control 53 PU/BK 5042 IMTV Solenoid Control 54 GY 1716 Low Reference 55 TN/WH 1669 HO2S Low Signal - Bank 1 Sensor 2 56 YE 492 MAF Sensor Signal 57 TN 472 IAT Sensor Signal 58 GY 2701 5-Volt Reference 59 PU/WH 5024 CKP Sensor Low 60 TN/WH 1653 HO2S Low Signal - Bank 1 Sensor 1 61 - - Not Used 62 BK 1705 Shielded Ground 63-64 - - Not Used

Engine Control Module (ECM) Connector End C2 Connector Part Information 1928403514 64-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1-3 - - Not Used 4 GY 23 Generator Field Duty Cycle Signal 5 GY 1884 Cruise Control Switch Signal 6 OG/BK 380 A/C Refrigerant Pressure Sensor Signal 7 TN 1274 5-Volt Reference 8 D-BU 1161 APP Sensor 1 Signal 9-10 - - Not Used 11 OG 225 Generator Turn On Signal 12 - - Not Used 13 D-GN/WH 459 A/C Compressor Clutch Relay Control 14 - - Not Used 15 RD/WH 1440 Battery Positive Voltage 16 PK/BK 5290 Ignition 1 Voltage 17 YE 5 Crank Voltage 18 WH 1310 EVAP Canister Vent Solenoid Control 19 BN 818 Vehicle Speed Signal 20 - - Not Used 21 BN/WH 379 CPP Switch Signal (M35) 22 L-BU 1937 Fuel Level Sensor Signal - Secondary 23 OG/BK 1786 Park/Neutral Signal (M82) PU/WH 1035 Starter Relay Coil Supply Voltage (M35) 24 BN 1271 Low Reference 25 PU 1272 Low Reference 26 - - Not Used 27 OG 5371 BAS Relay Coil Supply Voltage 28 OG/BK 463 Requested Torque Signal 29 - - Not Used 30 D-GN/WH 465 Fuel Pump Relay Control 31 BN 5069 Main Relay Control 32 PK/BK 5290 Ignition 1 Voltage 33 D-BU 473 High Speed Cooling Fan Relay Control 34 TN 452 Low Reference 35 WH 121 Engine Speed Signal 36 - - Not Used 37 D-GN 890 Fuel Tank Pressure Sensor Signal 38 D-BU 1936 Fuel Level Sensor Signal - Primary 39 YE 447 Starter Relay Coil Control 40 L-BU 1162 APP Sensor 2 Signal 41 GY 847 Extended Travel Brake Switch Signal 42-43 - - Not Used 44 YE 400 Vehicle Speed Sensor Signal (M35) 45 WH 2500 High Speed GMLAN Serial Data Bus+ (M82) 46 BN/WH 419 MIL Control 47 PK 239 Ignition 1 Voltage 48 PK/BK 5290 Ignition 1 Voltage 49 - - Not Used 50 D-GN 335 Low Speed Cooling Fan Relay Control 51 TN 470 Low Reference 52 TN/BK 464 Delivered Torque Signal 53 WH/BK 5043 Keyword 2000 Serial Data (M82) 54 - - Not Used 55 PU 1807 Class 2 Serial Data 56 WH/BK 1164 5-Volt Reference 57 PU 1807 Class 2 Serial Data 58-59 - - Not Used 60 YE/BK 5270 Traction Control Data Signal 61 L-GN 2501 High Speed GMLAN Serial Data Bus- (M82) 62 PU 5128 Auxiliary Cooling Fan Relay Control (Export w/V92) 63 TN 596 5-Volt Reference 64 YE 343 Accessory Voltage

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Engine Controls Connector End Views

Accelerator Pedal Position (APP) Sensor Connector End Connector Part Information 15326829 6-Way F 150 GT Series Sealed (BK) Pin Wire Color Circuit No. Function A PU 1272 Low Reference B L-BU 1162 APP Sensor 2 Signal C TN 1274 5-Volt Reference D BN 1271 Low Reference E D-BU 1161 APP Sensor 1 Signal F WH/BK 1164 5-Volt Reference

Camshaft Position (CMP) Sensor Connector End Connector Part Information 1928403870 3-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1 PK/BK 632 Low Reference 2 BN/WH 633 CMP Sensor Signal 3 PK/BK 5292 Ignition 1 Voltage

Crankshaft Position (CKP) Sensor Connector End Connector Part Information 1928403870 3-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1 WH/BK 5039 CKP Sensor High 2 PU/WH 5024 CKP Sensor Low 3 BK 1705 Shielded Ground

Engine Coolant Temperature (ECT) Sensor Connector End Connector Part Information 1928404476 2-Way F Bosch (WH) Pin Wire Color Circuit No. Function 1 YE 410 ECT Sensor Signal 2 TN 2761 Low Reference

Engine Oil Pressure (EOP) Sensor Connector End Connector Part Information CA400265 1-Way F Packard (BK) Pin Wire Color Circuit No. Function 1 TN/BK 231 Oil Pressure Switch Signal

Evaporative Emissions (EVAP) Canister Purge Solenoid Valve Connector End Connector Part Information 1928403698 2-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5705 Ignition 1 Voltage 2 D-GN/WH 428 EVAP Canister Purge Solenoid Control

Evaporative Emissions (EVAP) Canister Vent Solenoid Valve Connector End Connector Part Information 12052643 2-Way F Metri-Pack 150 Series Sealed (RD) Pin Wire Color Circuit No. Function A PK 1539 Ignition 1 Voltage B WH 1310 EVAP Canister Vent Solenoid Control

Fuel Injector 1 Connector End Connector Part Information 12131678 2-Way F Metri-Pack 280.1 Series, Sealed (BK) Pin Wire Color Circuit No. Function 1 RD/D-BU 5291 Ignition 1 Voltage 2 TN/YE 1744 Fuel Injector 1 Control

Fuel Injector 2 Connector End Connector Part Information 12131678 2-Way F Metri-Pack 280.1 Series, Sealed (BK) Pin Wire Color Circuit No. Function 1 RD/D-BU 5291 Ignition 1 Voltage 2 TN/L-GN 1745 Fuel Injector 2 Control

Fuel Injector 3 Connector End Connector Part Information 12131678 2-Way F Metri-Pack 280.1 Series, Sealed (BK) Pin Wire Color Circuit No. Function 1 RD/D-BU 5291 Ignition 1 Voltage 2 TN/D-BU 1746 Fuel Injector 3 Control

Fuel Injector 4 Connector End Connector Part Information 12131678 2-Way F Metri-Pack 280.1 Series, Sealed (BK) Pin Wire Color Circuit No. Function 1 RD/D-BU 5291 Ignition 1 Voltage 2 TN/RD 844 Fuel Injector 4 Control

Fuel Injector 5 Connector End Connector Part Information 12131678 2-Way F Metri-Pack 280.1 Series, Sealed (BK) Pin Wire Color Circuit No. Function 1 RD/D-BU 5291 Ignition 1 Voltage 2 TN/BK 845 Fuel Injector 5 Control

Fuel Injector 6 Connector End Connector Part Information 12131678 2-Way F Metri-Pack 280.1 Series, Sealed (BK) Pin Wire Color Circuit No. Function 1 RD/D-BU 5291 Ignition 1 Voltage 2 TN/WH 846 Fuel Injector 6 Control

Fuel Pump and Sender Assembly Connector End Connector Part Information 12160482 4-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A L-BU 1937 Fuel Level Sensor Signal - Primary B GY 120 Fuel Pump Supply Voltage C BK 1050 Ground D TN 2759 Low Reference

Fuel Tank Pressure (FTP) Sensor Connector End Connector Part Information 12059595 3-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A TN 2759 Low Reference B D-GN 890 Fuel Tank Pressure Sensor Signal C GY 2709 5-Volt Reference

Heated Oxygen Sensor (HO2S) Bank 1 Sensor 1 Connector End Connector Part Information 1928403453 4-Way M Bosch (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5293 Ignition 1 Voltage 2 L-BU 5038 HO2S Heater Low Control - Bank 1 Sensor 1 3 TN/WH 1653 HO2S Low Signal - Bank 1 Sensor 1 4 PU/WH 1665 HO2S High Signal - Bank 1 Sensor 1

Heated Oxygen Sensor (HO2S) Bank 1 Sensor 2 Connector End Connector Part Information 1928403453 4-Way M Bosch (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5294 Ignition 1 Voltage 2 PU 5035 HO2S Heater Low Control - Bank 1 Sensor 2 3 TN/WH 1669 HO2S Low Signal - Bank 1 Sensor 2 4 PU/WH 1668 HO2S High Signal - Bank 1 Sensor 2

Heated Oxygen Sensor (HO2S) Bank 2 Sensor 1 Connector End Connector Part Information 1928403453 4-Way M Bosch (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5293 Ignition 1 Voltage 2 PU/WH 5037 HO2S Heater Low Control - Bank 2 Sensor 1 3 TN 1667 HO2S Low Signal - Bank 2 Sensor 1 4 PU 1666 HO2S High Signal - Bank 2 Sensor 1

Heated Oxygen Sensor (HO2S) Bank 2 Sensor 2 Connector End Connector Part Information 1928403453 4-Way M Bosch (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5294 Ignition 1 Voltage 2 YE 5036 HO2S Heater Low Control - Bank 2 Sensor 2 3 TN 1671 HO2S Low Signal - Bank 2 Sensor 2 4 PU 1670 HO2S High Signal - Bank 2 Sensor 2

Ignition Coil Bank 1 Connector End Connector Part Information 1928403204 6-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1 BK/WH 1451 Ground 2 PK 739 Ignition 1 Voltage 3 D-GN 2125 IC 5 Control 4 L-BU 2123 IC 3 Control 5 PU 2121 IC 1 Control 6 - - Not Used

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Ignition Coil Bank 2 Connector End Connector Part Information 1928403815 6-Way F Bosch (GY) Pin Wire Color Circuit No. Function 1 BK/WH 1451 Ground 2 PK 739 Ignition 1 Voltage 3 OG/WH 2122 IC 2 Control 4 D-GN/WH 2124 IC 4 Control 5 L-BU/WH 2126 IC 6 Control 6 - - Not Used

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Intake Manifold Runner Control (IMRC) Solenoid Connector End Connector Part Information 12131678 2-Way F Packard (BK) Pin Wire Color Circuit No. Function 1 L-BU/WH 5041 IMRC Solenoid Control 2 PK/BK 5705 Ignition 1 Voltage

Intake Manifold Tuning Valve (IMTV) Solenoid Connector Part Information 12131678 2-Way F Packard (BK) Pin Wire Color Circuit No. Function 1 PU/BK 5042 IMTV Solenoid Control 2 PK/BK 5705 Ignition 1 Voltage

Knock Sensor (KS) Bank 1 Connector End Connector Part Information 1928403698 2-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1 D-BU 496 Knock Sensor 1 Signal 2 GY 1716 Low Reference

Knock Sensor (KS) Bank 2 Connector End Connector Part Information 1928403698 2-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1 L-BU 1876 Knock Sensor 2 Signal 2 TN 407 Low Reference

Mass Air Flow (MAF) Sensor Connector End Connector Part Information 1928404641 5-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1 TN 472 IAT Sensor Signal 2 PK/BK 5705 Ignition 1 Voltage 3 TN 2761 Low Reference 4 TN 2760 5-Volt Reference 5 YE 492 MAF Sensor Signal

Throttle Body Assembly Connector End Connector Part Information 1-967616-1 6-Way F Amp Power Quadlok (BK) Pin Wire Color Circuit No. Function 1 YE 581 TAC Motor Control - 1 2 TN 2752 Low Reference 3 GY 2701 5-Volt Reference 4 BN 582 TAC Motor Control - 2 5 PU 486 TP Sensor 2 Signal 6 D-GN 485 TP Sensor 1 Signal

Engine Control Module (ECM) Replacement

Removal Procedure

1. Using a scan tool, retrieve the percentage of remaining engine oil and the remaining automatic transmission fluid life. Record the remaining engine oil and the remaining automatic transmission fluid life.
2. Turn OFF the ignition.
3. Remove the screw (2) securing the engine control module (ECM) ground wire (1) to the ECM (3).
4. Flip the release levers to the open position (3) and disconnect the ECM connectors (2) from the ECM (5).
5. Remove the nuts securing the ECM to the ECM bracket.
6. Remove the ECM from the ECM bracket.

Installation Procedure

1. With the ignition off, position the ECM to the ECM bracket.
2. Install the nuts securing the ECM to the ECM bracket. Tighten: Tighten the ECM nuts to 8 N.m (71 lb in).
3. Carefully align the harness connectors (2) with the ECM connectors.
4. Guide the connectors (2) into place while moving the release levers to the locked position (1).
5. Install the screw (2) securing the ECM ground wire (1) to the ECM (3). Tighten: Tighten the ECM ground wire screw to 4.5 N.m (40 lb in).
6. Program the ECM. Refer to «Service Programming System (SPS)»(/cadillac/cts/i-2002-2007/remont/communication-devices/#service-programming-system) in Programming.
7. Program the theft deterrent system components if the ECM was installed from another vehicle. Refer to «Programming Theft Deterrent System Components»(/cadillac/cts/i-2002-2007/remont/door-locks-anti-theft-systems/#theft-deterrent-system) in Theft Deterrent.
8. Perform the idle learn procedure. Refer to «Idle Learn Procedure»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__idle-learn-procedure) .

Idle Learn Procedure

The engine control learns the idle position of the throttle body for correct operation. When the throttle body or ECM is replaced, this procedure must be performed to ensure correct idle operation. The engine idle may be unstable or a DTC may set if the idle position has not been learned.

Perform the following procedure in order to allow the ECM to learn the idle position

1. Ensure that the following conditions are met: The vehicle speed is 0 mph. The accelerator pedal angle is less than 14.9 percent. The battery voltage is more than 10 volts. The engine coolant temperature (ECT) is between 5-60°C (41-140°F). The intake air temperature (IAT) is more than 5-60°C (41-140°F).
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF for 1 minute.
4. Turn OFF the ignition.
5. Clear DTCs as necessary.

Engine Coolant Temperature (ECT) Sensor Replacement

1. Partially drain the coolant system. Refer to «Draining and Filling Cooling System (LA3, LY9)»(/cadillac/cts/i-2002-2007/remont/cooling-fan/#engine-cooling-system) or «Draining and Filling Cooling System (LY7)»(/cadillac/cts/i-2002-2007/remont/cooling-fan/#engine-cooling-system) or «Draining and Filling Cooling System (LS6)»(/cadillac/cts/i-2002-2007/remont/cooling-fan/#engine-cooling-system) in Engine Cooling.
2. Remove the wiper motor module in order to gain access to the engine coolant temperature (ECT) sensor. Refer to «Wiper Motor Module Replacement (LHD)»(/cadillac/cts/i-2002-2007/remont/wiperwasher-systems/#wiper-system-and-washer-system) or «Wiper Motor Module Replacement (RHD)»(/cadillac/cts/i-2002-2007/remont/wiperwasher-systems/#wiper-system-and-washer-system) in Wipers/Washer Systems.
3. Disconnect the electrical connector (3) from the ECT sensor.
4. Remove the ECT sensor from the water crossover.

1. Install the ECT sensor into the water crossover. Tighten: Tighten the engine coolant temperature (ECT) sensor to 18 N.m (13 lb ft).
2. Connect the electrical connector (3) to the ECT sensor.
3. Install the wiper motor module. Refer to «Wiper Motor Module Replacement (LHD)»(/cadillac/cts/i-2002-2007/remont/wiperwasher-systems/#wiper-system-and-washer-system) or «Wiper Motor Module Replacement (RHD)»(/cadillac/cts/i-2002-2007/remont/wiperwasher-systems/#wiper-system-and-washer-system) in Wipers/Washer Systems.
4. Fill the coolant system. Refer to «Draining and Filling Cooling System (LA3, LY9)»(/cadillac/cts/i-2002-2007/remont/cooling-fan/#engine-cooling-system) or «Draining and Filling Cooling System (LY7)»(/cadillac/cts/i-2002-2007/remont/cooling-fan/#engine-cooling-system) or «Draining and Filling Cooling System (LS6)»(/cadillac/cts/i-2002-2007/remont/cooling-fan/#engine-cooling-system) in Engine Cooling.

1. Disconnect the electrical connector (1) from the mass air flow (MAF)/intake air temperature (IAT) sensor (2).
2. Disconnect the air intake duct hose from MAF/IAT sensor.
3. Remove the 2 screws securing the MAF/IAT sensor to the air cleaner assembly.
4. Discard the MAF sensor seal.

1. Install a NEW MAF/IAT sensor seal.
2. Insert the MAF/IAT sensor into the air cleaner assembly with the connector terminal orientated upward.
3. Install the 2 screws securing the MAF/IAT sensor to the air cleaner assembly. Tighten: Tighten the MAF/IAT sensor screws to 2.25 N.m (20 lb in).
4. Connect the air intake duct hose to MAF/IAT sensor.
5. Connect the electrical connector (1) to the MAF/IAT sensor (2).

Tools Required

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

1. Disconnect the heated oxygen sensor connector (2) from the engine harness connector (1).
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/cts/i-2002-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Remove the heated oxygen sensor using the J 39194 . See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

1. Install the heated oxygen sensor using the J 39194 . See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) . Tighten: Tighten the heated oxygen sensor to 40 N.m (30 lb ft)
2. Lower the vehicle.
3. Connect the heated oxygen sensor connector (2) to the engine harness connector (1).

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

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/cts/i-2002-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Disconnect the heated oxygen sensor connector from the engine harness connector.
3. Remove the heated oxygen sensor using the J 39194 . See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

1. Install the heated oxygen sensor using the J 39194 . See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) . Tighten: Tighten the heated oxygen sensor to 40 N.m (30 lb ft).
2. Connect the heated oxygen sensor connector to the engine harness connector.
3. Lower the vehicle.

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

1. Disconnect the heated oxygen sensor connector (1) from the engine harness connector (2).
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/cts/i-2002-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Remove the heated oxygen sensor using the J 39194 . See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

1. Install the heated oxygen sensor using the J 39194 . See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) . Tighten: Tighten the heated oxygen sensor to 40 N.m (30 lb ft)
2. Lower the vehicle.
3. Connect the heated oxygen sensor connector (1) to the engine harness connector (2).

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

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/cts/i-2002-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Disconnect the heated oxygen sensor connector from the engine harness connector.
3. Remove the heated oxygen sensor using the J 39194 . See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

1. Install the heated oxygen sensor using the J 39194 . See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) . Tighten: Tighten the heated oxygen sensor to 40 N.m (30 lb ft).
2. Connect the heated oxygen sensor connector to the engine harness connector.
3. Lower the vehicle.

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1. Remove the closeout/insulator panel from under the dashboard on the drivers side. Refer to «Closeout/Insulator Panel Replacement - Left»(/cadillac/cts/i-2002-2007/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
2. Disconnect the accelerator pedal position (APP) sensor electrical connector from the accelerator pedal module.
3. Remove the APP sensor mounting bolts.
4. 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 9 N.m (80 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»(/cadillac/cts/i-2002-2007/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.

1. Partially drain the cooling system. Refer to «Draining and Filling Cooling System (LA3, LY9)»(/cadillac/cts/i-2002-2007/remont/cooling-fan/#engine-cooling-system) or «Draining and Filling Cooling System (LY7)»(/cadillac/cts/i-2002-2007/remont/cooling-fan/#engine-cooling-system) or «Draining and Filling Cooling System (LS6)»(/cadillac/cts/i-2002-2007/remont/cooling-fan/#engine-cooling-system) in Engine Cooling.
2. Disconnect the air intake duct hoses from the throttle body.
3. Disconnect the following from the throttle body: The surge tank inlet hose The throttle body heater hose The fuel pressure regulator atmospheric vent tube
4. Disconnect the throttle body electrical connector (2) from the throttle body (1).
5. Remove the throttle body assembly mounting bolts.
6. Remove the throttle body assembly from the following: The intake plenum The vacuum fittings
7. Remove and discard the following: The throttle body O-ring seals (1) The vacuum fitting O-ring seals

1. Position the throttle body O-ring seals (1) to the grooves in the throttle body.
2. Lightly lubricate the vacuum fitting O-rings with clean engine oil.
3. Install the vacuum fitting O-rings to the vacuum fittings.
4. Simultaneously position the throttle body assembly to the following: The intake plenum The vacuum fittings
5. Install the throttle body assembly mounting bolts. Tighten: Tighten the throttle body assembly mounting bolts to 8 N.m (71 lb in).
6. Connect the throttle body electrical connector (2) to the throttle body (1).
7. Connect the following to the throttle body: The surge tank inlet hose The throttle body heater hose The fuel pressure regulator atmospheric vent tube
8. Connect the air intake duct hoses to the throttle body.
9. Perform the idle learn procedure. Refer to «Idle Learn Procedure»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__idle-learn-procedure) .
10. Fill the cooling system. Refer to «Draining and Filling Cooling System (LA3, LY9)»(/cadillac/cts/i-2002-2007/remont/cooling-fan/#engine-cooling-system) or «Draining and Filling Cooling System (LY7)»(/cadillac/cts/i-2002-2007/remont/cooling-fan/#engine-cooling-system) or «Draining and Filling Cooling System (LS6)»(/cadillac/cts/i-2002-2007/remont/cooling-fan/#engine-cooling-system) in Engine Cooling.

1. Disconnect the air intake ducts from the throttle body.
2. Inspect the throttle body bore and the throttle valve plate for any deposits. It is necessary to open the throttle valve in order to inspect all of the surfaces.
3. Clean the throttle body bore and the throttle valve plate by using a clean shop towel with Top Engine Cleaner, GM P/N 1052626 (Canadian P/N 993026) or AC-Delco Carburetor Tune-Up Conditioner, P/N X66-P, or an equivalent product.

1. Connect the air intake ducts to the throttle body.
2. Inspect for air leaks.

Fuel Pressure Relief Procedure

Tools Required

1. J 34730-1A Fuel Pressure Gage
2. J 42242 Fuel Pressure Gage Adapter. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

1. Turn the ignition OFF.
2. Disconnect the battery negative cable in order to avoid possible fuel discharge if an accidental attempt is made to start the engine. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/cadillac/cts/i-2002-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
3. Loosen the fuel filler cap to relieve the fuel tank vapor pressure.
4. Remove the cap on the fuel pressure service connection.
5. Connect the J 34730-1A (1) and the J 42242 (2) to the fuel pressure service connection. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) . Wrap a shop towel around the fitting while connecting the gauge to avoid spillage.
6. Place the bleed hose of the J 34730-1A (1) into an approved gasoline container.
7. Open the bleed valve on the J 34730-1A (1) in order to bleed the fuel system pressure. The fuel connections are now safe for servicing.
8. Place a shop towel under the fuel pressure service connection to catch any remaining fuel spillage.
9. Remove both the J 34730-1A (1) and the J 42242 (2) from the fuel pressure service connection. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
10. Drain any fuel remaining in the J 34730-1A (1) into an approved gasoline container.
11. Install the cap on the fuel pressure service connection.

Tools Required

1. J 34730-1A Fuel Pressure Gage. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
2. J 42242 Fuel Pressure Gage Adapter. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

1. Remove the cap on the fuel pressure service connection.
2. Connect the J 34730-1A (1) and the J 42242 (2) to the fuel pressure service connection. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) . Wrap a shop towel around the fitting while connecting the gauge to avoid spillage.
3. Turn the ignition ON, with the engine OFF.
4. Place the bleed hose of the J 34730-1A (1) into an approved gasoline container.
5. Open the bleed valve on the J 34730-1A (1) in order to bleed the air from the fuel pressure gage.
6. Command the fuel pump ON with a scan tool.
7. Close the bleed valve on the J 34730-1A (1).
8. Inspect for fuel leaks.

1. Ensure the fuel pump is OFF
2. Place the bleed hose of the J 34730-1A (1) into an approved gasoline container.
3. Open the bleed valve on the J 34730-1A (1) in order to bleed the fuel system pressure.
4. Place a shop towel under the fuel pressure service connection to catch any remaining fuel spillage.
5. Remove both the J 34730-1A (1) and the J 42242 (2) from the fuel pressure service connection. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
6. Drain any fuel remaining in the J 34730-1A (1) and the J 42242 (2) into an approved gasoline container. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
7. Inspect for leaks using the following procedure: Turn the ignition ON, with the engine OFF for 2 seconds. Turn the ignition OFF, for 10 seconds. Turn the ignition ON, with the engine OFF for 2 seconds. Turn the ignition OFF. Inspect for leaks.
8. Install the cap on the fuel pressure service connection.

Quick Connect Fitting(s) Service (Metal Collar)

Tools Required

1. J 37088-A Fuel Line Disconnect Tool Set. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
2. J 44581 Fuel Line Disconnect Tool. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-pressure-relief-procedure) .
2. Remove the retainer from the quick-connect fitting.
3. Blow dirt out of the fitting using compressed air.
4. Depending on the fuel line size and ability to access the fitting, choose the appropriate tool, J 37088-A or. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) . J 44581 . See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) . Insert the J 37088-A into the female connector, then push inward to release the locking tabs. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
5. Pull the connection apart.
6. Using a clean shop towel, wipe off the male pipe end.
7. Inspect both ends of the fitting for dirt and burrs.
8. 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 to snap into place.
3. Pull on both sides of the quick-connect fitting to make sure the connection 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»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-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.

Fuel Filter Replacement

1. Keep a shop cloth and a container ready to capture any spilled fuel.
2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-pressure-relief-procedure) .
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/cts/i-2002-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Disconnect the quick-connect fitting at the fuel filter inlet. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__quick-connect-fittings-service-metal-collar) .
5. Using a primary and back-up wrench, remove the threaded fitting at the fuel filter outlet.
6. Slide the fuel filter rearward from the fuel filter bracket.
7. Remove the fuel pipe O-ring seal. Discard the O-ring seal if damaged.
8. Drain any remaining fuel into an approved gasoline container.
9. Discard the fuel filter into an approved container.

1. Lubricate the fuel pipe O-ring seal with clean engine oil.
2. Install the fuel pipe O-ring seal to the fuel pipe.
3. Remove the protective caps from the new fuel filter.
4. Slide the fuel filter forward into the fuel filter bracket.
5. Install the threaded fitting to the fuel filter outlet. Use a back-up wrench in order to prevent the fuel filter from turning. Tighten: Tighten the fuel filter outlet fitting to 30 N.m (22 lb ft).
6. Connect the quick-connect fitting at the fuel filter inlet. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__quick-connect-fittings-service-metal-collar) .
7. Lower the vehicle.

1. J 36850 Transjel Lubricant. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
2. J 42960-2 Fuel Flapper Door Holder. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
3. J 45004 Fuel Drain Hose. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

Draining Procedure

1. Remove the fuel filler cap.
2. Install the J 42960-2 into the fuel fill pipe in order to hold the door open. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
3. Insert the J 45004 into the fuel tank until the hose reaches the bottom of the fuel tank. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
4. Use an air operated pump device in order to drain the fuel into an approved gasoline container. Up to 26 liters (7 gallons) of residual fuel may remain in the secondary side of the fuel tank.
5. Simultaneously twist and pull in order to remove the J 45004 from the fuel tank. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

Fuel Tank Replacement

1. Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-pressure-relief-procedure) .
3. Remove the exhaust system. Refer to «Exhaust System Replacement (LA3, LY9)»(/cadillac/cts/i-2002-2007/remont/exhaust/#engine-exhaust-system__exhaust-system-replacement-la3-ly9) or «Exhaust System Replacement (LY7)»(/cadillac/cts/i-2002-2007/remont/exhaust/#engine-exhaust-system) or «Exhaust System Replacement (LS6)»(/cadillac/cts/i-2002-2007/remont/exhaust/#engine-exhaust-system__exhaust-system-replacement-ls6) in Engine Exhaust.
4. Remove the propeller shaft. Refer to «Propeller Shaft Replacement (Automatic Transmission)»(/cadillac/cts/i-2002-2007/remont/driveshaft-universal-joints/#propeller-shaft) or «Propeller Shaft Replacement (Manual Transmission)»(/cadillac/cts/i-2002-2007/remont/driveshaft-universal-joints/#propeller-shaft) or «Propeller Shaft Replacement (CTS-V)»(/cadillac/cts/i-2002-2007/remont/driveshaft-universal-joints/#propeller-shaft) in Propeller Shaft.
5. Disconnect the filler hose (1) from the fuel tank.
6. Disconnect the filler vent tube (2) from the evaporative emission (EVAP) hose. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
7. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) in order to disconnect the following from the chassis bundle: The fuel feed hose The fuel return hose The fuel EVAP hose
8. Disconnect the fuel tank electrical connector.
9. Disconnect the EVAP hoses from the EVAP canister.
10. Pull outward on the retainer tab in order to disengage the retainer from the chassis.
11. Disconnect the electrical connector from the EVAP canister.
12. Raise the lower control arms using a suitable screw jack (3) in order to remove the load from the lower shock bolts (2).
13. Remove the lower shock bolts (2).
14. Remove the screw jack (3).
15. Position the screw jack under the rear frame near the adjuster tie bar, in order to support the front of the rear frame.
16. Remove the 2 front bolts from the rear frame.
17. Lower the screw jack until there is approximately 50 mm (2 in) (a) between the front mounting surface of the rear frame and the chassis. This will allow clearance to access the fuel tank strap bolts.
18. Remove the fuel tank strap bolts.
19. Position the fuel tank straps downward around the rear frame.
20. Carefully bend the fuel tank straps ONLY enough to allow the fuel tank to be removed.
21. With the aid of an assistant, carefully lower the fuel tank from the vehicle.
22. Remove the following components if replacing just the fuel tank: The primary fuel tank module. Refer to «Fuel Tank Module Replacement - Primary»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) . The secondary fuel tank module. Refer to «Fuel Tank Module Replacement - Secondary»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) . The fuel tank pressure sensor. Refer to «Fuel Tank Pressure Sensor Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

1. Install the following components if fuel tank replacement was necessary: The primary fuel tank module. Refer to «Fuel Tank Module Replacement - Primary»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) . The secondary fuel tank module. Refer to «Fuel Tank Module Replacement - Secondary»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) . The fuel tank pressure sensor. Refer to «Fuel Tank Pressure Sensor Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
2. Pressure test the fuel tank. Refer to «Fuel Tank Leak Test»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-troubleshooting) .
3. With the aid of an assistant, carefully raise the fuel tank to the vehicle, aligning the filler neck with the filler hose.
4. Carefully bend the fuel tank straps back to their original form.
5. Position the fuel tank straps around the rear frame and upward into position, aligning the holes in the straps with the threaded holes in the chassis.
6. Install the fuel tank strap bolts. Tighten: Tighten the fuel tank strap bolts to 50 N.m (37 lb ft).
7. Connect the filler hose (1) to the fuel tank. Tighten: Tighten the fuel filler tube hose clamp (3) to 3.5 N.m (31 lb in).
8. Connect the filler vent tube (2) to the EVAP hose. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
9. Connect the EVAP hoses to the EVAP canister.
10. Insert the retainer into the chassis and press inward on the tab to engage.
11. Connect the electrical connector to the EVAP canister.
12. Connect the fuel tank electrical connector.
13. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) in order to connect the following to the chassis bundle: The fuel feed hose The fuel return hose The fuel EVAP hose
14. Raise the rear frame using the screw jack.
15. Install the 2 front bolts to the rear frame. Tighten: Tighten the rear frame bolts to 200 N.m (148 lb ft).
16. Remove the screw jack.
17. Position the screw jack (3) under the lower control arm in order to raise the lower control arms (2).
18. Install the lower shock bolts (2). Tighten: Tighten the lower shock bolts to 90 N.m (66 lb ft).
19. Remove the screw jack (3).
20. Install the propeller shaft. Refer to «Propeller Shaft Replacement (Automatic Transmission)»(/cadillac/cts/i-2002-2007/remont/driveshaft-universal-joints/#propeller-shaft) or «Propeller Shaft Replacement (Manual Transmission)»(/cadillac/cts/i-2002-2007/remont/driveshaft-universal-joints/#propeller-shaft) or «Propeller Shaft Replacement (CTS-V)»(/cadillac/cts/i-2002-2007/remont/driveshaft-universal-joints/#propeller-shaft) in Propeller Shaft.
21. Install the exhaust system. Refer to «Exhaust System Replacement (LA3, LY9)»(/cadillac/cts/i-2002-2007/remont/exhaust/#engine-exhaust-system__exhaust-system-replacement-la3-ly9) or «Exhaust System Replacement (LY7)»(/cadillac/cts/i-2002-2007/remont/exhaust/#engine-exhaust-system) or «Exhaust System Replacement (LS6)»(/cadillac/cts/i-2002-2007/remont/exhaust/#engine-exhaust-system__exhaust-system-replacement-ls6) in Engine Exhaust.
22. Refill the fuel tank.
23. Inspect for fuel leaks.

1. Remove the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-tank-replacement) .
2. Disconnect the electrical connector from the fuel tank pressure sensor.
3. Open the retaining strap.
4. Carefully pry the locking tabs away from the pressure sensor.
5. Pull upward in order to remove the pressure sensor from the fuel tank.

1. Press the fuel tank pressure sensor into the fuel tank, until the locking tabs are fully seated.
2. Close the retaining strap.
3. Connect the electrical connector to the fuel tank pressure sensor.
4. Install the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-tank-replacement) .

1. Remove the fuel filler cap.
2. Drain the fuel tank below the level of the fuel filler hose. Refer to «Fuel Tank Draining Procedure»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
3. Remove the bolts securing the fuel filler tube to the body.
4. Remove the right rear wheel. Refer to «Tire and Wheel Removal and Installation»(/cadillac/cts/i-2002-2007/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
5. Remove the right rear fascia extension. Refer to «Fascia Extension Replacement - Rear»(/cadillac/cts/i-2002-2007/remont/exterior-body-panels/#bumpers-fascias) in Bumpers.
6. Remove the fuel filler tube brace bolt.
7. Disconnect the fuel filler hose (1) from the fuel tank.
8. Disconnect the filler vent tube (2) from the evaporative emission (EVAP) hose. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
9. Remove the fuel filler tube from the vehicle.

1. Position the fuel filler tube to the vehicle.
2. Connect the filler hose (1) to the fuel tank. Tighten: Tighten the fuel filler tube hose clamp (3) to 3.5 N.m (31 lb in).
3. Connect the filler vent tube (2) to the EVAP hose. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
4. Install the fuel filler tube brace bolt. Tighten: Tighten the fuel filler tube brace bolt to 9 N.m (80 lb in).
5. Install the bolts securing the fuel filler tube to the body. Tighten: Tighten the fuel filler tube bolts to 3.5 N.m (31 lb in).
6. Install the right rear fascia extension. Refer to «Fascia Extension Replacement - Rear»(/cadillac/cts/i-2002-2007/remont/exterior-body-panels/#bumpers-fascias) in Bumpers.
7. Install the right rear wheel. Refer to «Tire and Wheel Removal and Installation»(/cadillac/cts/i-2002-2007/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
8. Add fuel to the fuel tank.
9. Inspect for fuel leaks.
10. Install the fuel filler cap.

J 45747 Fuel Tank Sender Wrench. See Special Tools and Equipment .

1. Remove the fuel tank hoses. Refer to «Fuel Hoses/Pipes Replacement - Filter to Tank»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
2. Disconnect the electrical connector from the primary fuel tank module.
3. Rotate the cam lock ring counter-clockwise using the J 45747 . See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
4. Remove the cam lock ring from the fuel tank.
5. Carefully lift the primary fuel tank module (1) from the fuel tank only enough to access the transfer tube (2).
6. Complete the following in order to disconnect the transfer tube from the primary fuel tank module: Pull the locking mechanism away from the module. Remove the transfer tube from the module.
7. Remove the primary fuel tank module from the fuel tank.
8. Remove the primary fuel tank module seal from the module. Do not reuse the seal.

1. Place the new primary fuel tank module seal (1) over the module (2).
2. Complete the following in order to connect the transfer tube (2) to the primary fuel tank module (1). Grasp the transfer tube (2) from inside the fuel tank. Position the module (1) near the module opening. Connect the transfer tube (2) to the module (1).
3. Carefully insert the primary fuel tank module (1) into the fuel tank.
4. Press the primary fuel tank module (1) downward, aligning the module to the encapsulated ring.
5. Position the cam lock ring to the fuel tank.
6. Rotate the cam lock ring clockwise using the J 45747 until fully seated. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
7. Connect the electrical connector to the primary fuel tank module.
8. Install the fuel tank hoses. Refer to «Fuel Hoses/Pipes Replacement - Filter to Tank»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

J 45747 Fuel Tank Sender Wrench. See Special Tools and Equipment .

1. Remove the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-tank-replacement) .
2. Disconnect the electrical connector from the secondary fuel tank module.
3. Rotate the cam lock ring counter-clockwise using the J 45747 . See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
4. Remove the cam lock ring from the fuel tank.
5. Carefully lift the secondary fuel tank module (2) from the fuel tank only enough to access the transfer tube (1).
6. Complete the following in order to disconnect the transfer tube from the secondary fuel tank module. Pull the locking mechanism away from the module. Remove the transfer tube from the module.
7. Remove the secondary fuel tank module from the fuel tank.
8. Remove the secondary fuel tank module seal from the module. Do not reuse the seal.

1. Place the new secondary fuel tank module seal (1) over the module (2).
2. Complete the following in order to connect the transfer tube (1) to the secondary fuel tank module (2). Grasp the transfer tube (1) from inside the fuel tank. Position the module (2) near the module opening. Connect the transfer tube (1) to the module (2).
3. Carefully insert the secondary fuel tank module (2) into the fuel tank.
4. Press the secondary fuel tank module (2) downward, aligning the module to the encapsulated ring.
5. Position the cam lock ring to the fuel tank.
6. Rotate the cam lock ring clockwise using the J 45747 until fully seated. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
7. Connect the electrical connector to the secondary fuel tank module.
8. Install the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-tank-replacement) .

Fuel Level Sensor Replacement - Primary

1. Remove the primary fuel tank module. Refer to «Fuel Tank Module Replacement - Primary»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
2. Disconnect the fuel level sensor electrical connector (1) from the module.
3. Complete the following in order to remove the fuel level sensor (1) from the module assembly: Pull the locking tab (2) away from the sensor (1). Slide the sensor (1) away from the module assembly.

1. Complete the following in order to install the fuel level sensor (1) to the module assembly: Align the tabs of the sensor (1) with the slots in the module assembly. Slide the sensor (1) fully into position, ensure the locking tab (2) is engaged.
2. Connect the fuel level sensor electrical connector (1) to the module.
3. Install the primary fuel tank module. Refer to «Fuel Tank Module Replacement - Primary»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

1. Remove the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-tank-replacement) .
2. Disconnect the following from the primary fuel tank module: The pressure hose The return hose
3. Disconnect the hoses from the retaining feature at the fuel tank.

1. Clean any contamination from the male pipe ends of the primary fuel tank module.
2. Connect the hoses to the retaining feature at the fuel tank.
3. Connect the following to the primary fuel tank module: The pressure hose The return hose
4. Install the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-tank-replacement) .

The fuel system hose/pipes are serviceable individually or as a complete fuel/brake bundle assembly, the following procedure is servicing the fuel hose/pipes individually.

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-pressure-relief-procedure) .
2. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__quick-connect-fittings-service-metal-collar) in order to disconnect the following quick connect fittings from the fuel rail: The return hose/pipe (1) The feed hose/pipe (2) Plug the open outlet ports to prevent fuel loss and contamination.
3. Disconnect the evaporative emission (EVAP) quick connect fitting (3). Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
4. Open the retainer (4) located at the engine control module (ECM) bracket in order to remove the chassis hose/pipes.
5. Open the retainer located at the shock tower in order to remove the chassis hose/pipes.
6. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/cts/i-2002-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
7. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) in order to disconnect the following quick connect fittings from the chassis bundle: The fuel filter The fuel return hose The fuel EVAP hose Plug the open outlet ports to prevent fuel loss and contamination.
8. Pull the locking mechanism (1) outward in order to disengage the fuel/brake bundle chassis pipe retainers from the rail.
9. Open the retainers (1) located at the forward portion of the rail in order to remove the chassis hose/pipes.
10. Complete the following in order to remove the chassis hose/pipes from the retainers (2) located at the rearward portion of the rail: Pull the retainers (2) free from the rail. Open the retainers (2) at the top. Remove the chassis hose/pipes from the retainers (2).
11. Pull downward in order to disconnect the fuel/brake bundle chassis pipe retainer from the underbody.
12. Remove the bolt securing the fuel filter bracket to the body.
13. Remove the following from the fuel filter bracket: The fuel return hose The fuel EVAP hose
14. Remove the bolts securing the transmission support to the underbody, from the right side only.
15. Pull the right side transmission support down only enough to allow removal of the chassis fuel hose/pipes.
16. Partially lower the hoist only enough to simultaneously gain access to both the front and rear portions of the chassis fuel hose/pipes.
17. With the aid of an assistant, carefully guide the chassis fuel hose/pipes down through the engine compartment, removing from the bottom.

1. Clean any of the contamination from the male line ends and apply a few drops of clean engine oil.
2. With the aid of an assistant, carefully guide the chassis fuel hose/pipes up through the engine compartment into position.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/cts/i-2002-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Pull the right side transmission support down only enough to allow installation of the chassis fuel hose/pipes.
5. Install the bolts securing the transmission support to the underbody. Tighten: Tighten the transmission support bolts to 60 N.m (44 lb ft).
6. Install the following to the fuel filter bracket: The fuel return hose The fuel EVAP hose
7. Install the bolt securing the fuel filter bracket to the body. Tighten: Tighten the fuel filter bracket bolt to 9 N.m (80 lb in).
8. Push upward in order to connect the fuel/brake bundle chassis pipe retainer to the underbody.
9. Complete the following in order to install the chassis hose/pipes to the retainers (2) located at the rearward portion of the rail: Install the chassis hose/pipes into the retainers (2). Close the retainers (2) at the top. Insert the retainers (2) into the rail.
10. Install the chassis hose/pipes into the retainers (1) located at the forward portion of the rail.
11. Close the retainers.
12. Push the locking mechanism (1) inward in order to engage the fuel/brake bundle chassis pipe retainers to the rail.
13. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) in order to connect the following quick connect fittings to the chassis bundle: The fuel filter The fuel return hose The fuel EVAP hose
14. Lower the vehicle.
15. Insert the chassis hose/pipes into the retainer located at the shock tower.
16. Close the retainer.
17. Insert the chassis hose/pipes into the retainer (4) located at the ECM bracket.
18. Close the retainer (4).
19. Connect the EVAP quick connect fitting (3). Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
20. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__quick-connect-fittings-service-metal-collar) in order to connect the following quick connect fittings to the fuel rail: The feed hose/pipe (2) The return hose/pipe (1)

Fuel System Cleaning

The following procedure covers the disassembly and the inspection of the complete fuel supply system. If the fuel system is contaminated, the fuel system can be cleaned. You can usually determine the extent of the fuel system contamination during the disassembly.

1. Remove the in-line fuel filter. Refer to «Fuel Filter Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-filter-replacement) .
2. Inspect the fuel system for contamination of the in-line fuel filter. Replace the filter after cleaning the fuel lines if the filter is plugged or contaminated.
3. Remove the fuel module assemblies. Refer to «Fuel Tank Module Replacement - Primary»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) and «Fuel Tank Module Replacement - Secondary»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
4. Locate the tank in a suitable work area away from any heat, any flame, or any other source of ignition.
5. Perform the following procedures: Inspect the fuel sender strainer. Replace the primary fuel tank module if the strainer is contaminated. Inspect the secondary fuel tank module for debris. Clean the secondary fuel tank module if debris is found. CAUTION: Wear safety glasses when using compressed air, as flying dirt particles may cause eye injury. Use compressed air in order to apply air pressure to the transfer tube.
6. Flush the fuel tank with running hot water for at least five minutes. Pour the water out of the fuel sender assembly opening. Rock the tank in order to ensure that the removal of the water from the tank is complete.
7. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__quick-connect-fittings-service-metal-collar) in order to disconnect the following quick connect fittings from the fuel rail: The feed hose/pipe The return hose/pipe
8. Use compressed air in order to apply air pressure to the fuel lines in the opposite direction from the normal fuel flow.
9. Remove the fuel injectors and fuel rail. Refer to «Fuel Injectors and Fuel Rail Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
10. Clean and inspect the fuel injectors and fuel rail.

Assemble the fuel system as follows

1. Install the fuel injectors and fuel rail. Refer to «Fuel Injectors and Fuel Rail Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
2. Install the fuel module assemblies. Refer to «Fuel Tank Module Replacement - Primary»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) and «Fuel Tank Module Replacement - Secondary»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
3. Install the fuel filter. Refer to «Fuel Filter Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-filter-replacement) .
4. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__quick-connect-fittings-service-metal-collar) in order to connect the following quick connect fittings to the fuel rail: The feed hose/pipe The return hose/pipe

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-pressure-relief-procedure) .
2. Remove the air inlet grill in order to gain access to the fuel pressure regulator. Refer to «Air Inlet Grille Panel Replacement (LHD)»(/cadillac/cts/i-2002-2007/remont/exterior-body-panels/#body-front-end) or «Air Inlet Grille Panel Replacement (RHD)»(/cadillac/cts/i-2002-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
3. Place a shop towel under the fuel pressure regulator to absorb any lost fuel when removing the regulator.
4. Disconnect the atmospheric vent hose from the fuel pressure regulator.
5. Remove the fuel pressure regulator clamp bolt.
6. Spread the clamp only enough to allow the fuel pressure regulator to be removed.
7. Twist while pulling outward in order to remove the fuel pressure regulator from the fuel rail.

Scheme 165

1. Apply a few drops of clean engine oil to the O-ring seals on the fuel pressure regulator.
2. Twist while pushing inward on the fuel pressure regulator, until fully seated against the fuel rail.
3. Position the clamp around both the fuel pressure regulator and the fuel rail.
4. Install the fuel pressure regulator clamp bolt. Tighten: Tighten the fuel pressure regulator clamp bolt to 5 N.m (44 lb in).
5. Install the atmospheric vent hose on to the fuel pressure regulator port.
6. Using the scan tool turn ON the fuel pump to pressurize the system.
7. Check for fuel leaks.
8. Install the air inlet grill. Refer to «Air Inlet Grille Panel Replacement (LHD)»(/cadillac/cts/i-2002-2007/remont/exterior-body-panels/#body-front-end) or «Air Inlet Grille Panel Replacement (RHD)»(/cadillac/cts/i-2002-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-pressure-relief-procedure) .
2. Remove the intake plenum. Refer to «Intake Plenum Replacement»(/cadillac/cts/i-2002-2007/remont/mechanical/#engine-mechanical-32l) in Engine Mechanical-2.6L and 3.2L.
3. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__quick-connect-fittings-service-metal-collar) in order to disconnect the following quick connect fittings from the fuel rail: The return hose/pipe (1) The feed hose/pipe (2)
4. Remove the fuel rail brace bolt from the intake manifold.
5. Disconnect the fuel injector electrical connectors from each fuel injector.
6. Unclip the harness from the fuel rail and position aside.
7. Disconnect the atmospheric vent hose from the fuel pressure regulator.
8. Remove the bolts securing the fuel rail to the intake manifold.
9. Use compressed air in order to blow dirt out of the area where the injectors enter the intake casting.
10. Carefully lift the fuel rail assembly from the intake manifold.
11. Remove the retainers from the fuel injectors.
12. Remove the fuel injectors from the fuel rail.
13. Remove the O-ring seals from the fuel injectors. Discard the O-ring seals.

1. Lubricate the new fuel injector O-ring seals with clean engine oil.
2. Install the new fuel injector O-ring seals on to the fuel injectors.
3. Install the fuel injectors to the fuel rail with the new retainer clips.
4. Ensure that the injectors are aligned by orienting the electrical connectors perpendicular to the crankshaft centerline.
5. Align the fuel injectors and fuel rail to the intake manifold.
6. Carefully press the fuel rail assembly downward until fully seated against the intake manifold.
7. Install the fuel rail with the injectors to the intake manifold.
8. Install the bolts securing the fuel rail to the intake manifold. Tighten: Tighten the fuel rail bolts to 8 N.m (71 lb in).
9. Connect the atmospheric vent hose to the fuel pressure regulator.
10. Clip the fuel injector electrical harness to the fuel rail.
11. Connect the fuel injector electrical connectors to each fuel injector.
12. Install the fuel rail brace bolt to the intake manifold. Tighten: Tighten the fuel rail brace bolt to 8 N.m (71 lb in).
13. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__quick-connect-fittings-service-metal-collar) in order to connect the following quick connect fittings to the fuel rail: The feed hose/pipe (2) The return hose/pipe (1)
14. Install the intake plenum. Refer to «Intake Plenum Replacement»(/cadillac/cts/i-2002-2007/remont/mechanical/#engine-mechanical-32l) in Engine Mechanical-2.6L and 3.2L.

1. Loosen the fuel filler cap in order to relieve the system pressure.
2. Disconnect the evaporative emission (EVAP) canister purge valve vacuum hose (1) from the engine vent adapter (2).
3. Disconnect the electrical connector (2) from the coil pack (1).
4. Disconnect the EVAP quick connect fitting. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
5. Remove the heated oxygen sensor connector (1) from the bracket (3).
6. Disconnect the electrical connector (1) from the EVAP canister purge valve.
7. Remove the bolt (6) securing the following to the crankcase vent housing (4): The heated oxygen sensor connector bracket (5) The EVAP canister purge valve bracket (1)
8. Remove the EVAP canister purge valve assembly from the engine.

1. Position the EVAP canister purge valve assembly behind the intake plenum as previously noted during disassembly.
2. Install the bolt (6) securing the following to the crankcase vent housing (4): The heated oxygen sensor connector bracket (5) The EVAP canister purge valve bracket (1) Tighten: Tighten the EVAP canister purge valve bracket bolt to 8 N.m (71 lb in).
3. Connect the electrical connector (1) to the EVAP canister purge valve.
4. Install the heated oxygen sensor connector (1) to the bracket (3).
5. Connect the EVAP quick connect fitting. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
6. Connect the electrical connector (2) to the coil pack (1).
7. Connect the EVAP canister purge valve vacuum hose (1) to the engine vent adapter (2).
8. Tighten the fuel filler cap.

1. Remove the evaporative emission (EVAP) canister. Refer to «Evaporative Emission (EVAP) Canister Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
2. Clean away any debris that may be present around the EVAP canister vent valve.
3. Twist the EVAP canister vent valve counter-clockwise.
4. Pull the EVAP canister vent valve from the EVAP canister.

1. Insert the EVAP canister vent valve into the EVAP canister.
2. Twist the EVAP canister vent valve clockwise into the locked position.
3. Install the EVAP canister. Refer to «Evaporative Emission (EVAP) Canister Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

Note. Do not attempt to straighten kinked nylon pipes. Replace any kinked nylon pipes in order to prevent damage to the vehicle. Do not attempt to repair sections of nylon pipes. Replace damaged nylon pipes. Replace the vapor hoses/pipes with original equipment or parts that meet GM specifications.

1. Remove the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-tank-replacement) .
2. Remove the chassis to canister evaporative emission (EVAP) hose from the following: The body retainer (1) The 3 retaining features (2) on the fuel tank The retainer clip (3)
3. Remove the EVAP hose from the fuel tank.

1. Position the EVAP hose to the fuel tank.
2. Install the chassis to canister evaporative emission (EVAP) hose to the following: The body retainer (1) The 3 retaining features (2) on the fuel tank The retainer clip (3)
3. Install the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-tank-replacement) .

1. Remove the rear frame. Refer to «Frame Replacement - Rear»(/cadillac/cts/i-2002-2007/remont/frames-subframes-crossmembers/#frame-and-underbody) in Frame and Underbody.
2. Disconnect the evaporative emission (EVAP) hoses from the EVAP canister.
3. Disconnect the electrical connector from the EVAP canister.
4. Remove the EVAP canister retaining nuts.
5. Complete the following in order to remove the EVAP canister: Lower the rear of the canister enough to clear the 2 weld studs. Slide the canister rearward from the body brace.

1. Complete the following in order to install the EVAP canister: Insert the fresh air tube and tab on the canister forward into the body brace. Rotate the rear of the canister up over the 2 weld studs on the floor pan.
2. Install the EVAP canister retaining nuts. Tighten: Tighten the EVAP canister retaining nuts to 6 N.m (53 lb in).
3. Connect the EVAP hoses to the EVAP canister.
4. Connect the electrical connector to the EVAP canister.
5. Install the rear frame. Refer to «Frame Replacement - Rear»(/cadillac/cts/i-2002-2007/remont/frames-subframes-crossmembers/#frame-and-underbody) in Frame and Underbody.

Scheme 166

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/cts/i-2002-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Using a 90 degree pick, disengage the lower filter cover clips.
3. Insert a flat-bladed tool between the filter cover and canister, and push up to disengage the upper clips.
4. Remove and discard the evaporative emission (EVAP) canister filter cover.
5. Remove and discard the EVAP canister filter.
6. Clean the inside of the EVAP canister filter housing with a clean shop towel.

1. Insert a NEW EVAP canister filter into the EVAP canister.
2. Install a NEW EVAP canister filter cover seal to a EVAP NEW canister cover.
3. Snap the EVAP canister filter cover onto the EVAP canister.
4. Lower the vehicle.

J 43301 Coil Pack Remover. See Special Tools and Equipment .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__fuel-pressure-relief-procedure) .
2. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__quick-connect-fittings-service-metal-collar) in order to disconnect the following quick connect fittings from the fuel rail. The return hose/pipe (1) The feed hose/pipe (2) Plug the open outlets to prevent fluid loss and contamination.
3. Disconnect the evaporative emission (EVAP) quick connect fitting (3). Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
4. Open the retainer (4) located at the engine control module (ECM) bracket in order to remove the chassis hose/pipes.
5. Disconnect the 2 cable harness clips (1) securing the engine wiring harness (4) to the ECM bracket (2).
6. Remove the 2 bolts (3) securing the afterboil coolant pump to the ECM bracket, and position aside.
7. Remove the screw (2) securing the engine control module (ECM) ground wire (1) to the ECM (3).
8. Flip the release levers to the open position (3) and disconnect the ECM connectors (2) from the ECM (5).
9. Remove the bolt securing the coolant inlet pipe to the ECM bracket.
10. Remove the ECM bracket bolts from the following: The intake plenum The cylinder head
11. Remove the ECM bracket from the engine with the ECM still attached, and position aside.
12. Disconnect the electrical connector (2) from the right knock sensor pigtail (1).
13. Disconnect the electrical connector (2) from the coil pack (1).
14. Remove the coil pack retainer bolts.
15. Thread the J 43301 into the coil pack.
16. With even pressure, lift and remove the coil pack from the cam cover.

1. Inspect the coil pack seals and spark plug boots for damage or wear. Replace as necessary.
2. Align the spark plug boots with the spark plugs.
3. Carefully press and seat the coil pack in place.
4. Install the coil pack retainer bolts. Tighten: Tighten the coil pack retainer bolts to 8 N.m (71 lb in).
5. Connect the electrical connector (2) to the coil pack (1).
6. Connect the electrical connector (2) to the right knock sensor pigtail (1).
7. Position the ECM and bracket to the engine.
8. Install the ECM bracket bolts to the following: The cylinder head The intake plenum
9. Tighten the ECM bracket bolts in the sequence shown. Tighten: Tighten the ECM bracket to cylinder head bolt to 20 N.m (15 lb ft). Tighten the ECM bracket to intake plenum bolts to 8 N.m (71 lb in).
10. Install the bolt securing the coolant inlet pipe to the ECM bracket. Tighten: Tighten the coolant inlet pipe support bolt to 20 N.m (15 lb ft).
11. Carefully align the harness connectors (2) with the ECM connectors.
12. Guide the connectors (2) into place while moving the release levers to the locked position (1).
13. Install the screw (2) securing the ECM ground wire (1) to the ECM (3). Tighten: Tighten the ECM ground wire screw to 4.5 N.m (40 lb in).
14. Install the 2 bolts (3) securing the afterboil coolant pump to the ECM bracket. Tighten: Tighten the afterboil coolant pump bolts to 10 N.m (89 lb in).
15. Connect the 2 cable harness clips (1) securing the engine wiring harness (4) to the ECM bracket (2).
16. Insert the chassis hose/pipes into the retainer (4) located at the ECM bracket.
17. Close the retainer (4).
18. Connect the EVAP quick connect fitting (3). Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
19. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__quick-connect-fittings-service-metal-collar) in order to connect the following quick connect fittings to the fuel rail. The feed hose/pipe (2) The return hose/pipe (1)

J 43301 Coil Pack Remover. See Special Tools and Equipment .

1. Remove the oil filler spout by unlocking the tab and twisting counterclockwise.
2. Disconnect the following from the remote power steering fluid reservoir (1): The vacuum brake booster hose The wiring harness (2)
3. Disconnect the vacuum brake booster hose from the vacuum source.
4. Remove the remote power steering fluid reservoir mounting bolts (1, 3) ONLY, and position aside.
5. Disconnect the electrical connector (2) from the coil pack (1).
6. Remove the coil pack retainer bolts.
7. Thread the J 43301 into the coil pack.
8. With even pressure, lift and remove the coil pack from the cam cover.

1. Inspect the coil pack seals and spark plug boots for damage or wear. Replace as necessary.
2. Align the spark plug boots with the spark plugs.
3. Carefully press and seat the coil pack in place.
4. Install the coil pack retainer bolts. Tighten: Tighten the coil pack retainer bolts to 8 N.m (71 lb in).
5. Connect the electrical connector (2) to the coil pack (1).
6. Install the remote power steering fluid reservoir mounting bolts (1, 3). Tighten Tighten the remote power steering fluid reservoir to intake plenum mounting bolts (1) to 9 N.m (80 lb in). Tighten the remote power steering fluid reservoir to cylinder head mounting bolt (3) to 25 N.m (18 lb ft).
7. Connect the following to the remote power steering fluid reservoir (1): The vacuum brake booster hose The wiring harness (2)
8. Connect the vacuum brake booster hose to the vacuum source.
9. Install the oil filler spout by twisting clockwise and snapping in place.

Spark Plug Operation

Worn or dirty spark plugs may operate well at idle speeds, but frequently fail at higher load. Bad spark plugs are often responsible for the following conditions

1. Power loss
2. Poor fuel economy
3. Loss of speed
4. Hard starting
5. Poor engine performance

Normal spark plug operation results in brown to grayish tan deposits on the area of the spark plug that enters the cylinder. A small amount of reddish brown, yellow, and white powdery residue may also be present on the insulator tip around the center electrode. These deposits are normal combustion by-products of fuels and lubricating oils which contain additives.

Misfiring is a general term that applies to a poor running engine. With misfiring, the ignition spark is not igniting the air/fuel mixture at the proper time. While other possible causes must be investigated, the spark plugs should be inspected first. Spark voltage should not reach ground before jumping across the gap at the tip of the spark plug. This leaves the air/fuel mixture unburned, causing misfiring. Pre-ignition misfiring occurs when the spark plug tip overheats, igniting the mixture before the spark jumps.

Carbon fouling of the spark plug is indicated by dry carbon deposits on the portion of the spark plug inside of the cylinder. Excess idling and driving at slower speeds under light engine loads can keep the spark plug temperatures so low that these deposits are not burned off. Rich fuels or poor ignition system output may also cause carbon fouling.

Oil fouling of the spark plug appears as wet oily deposits on the portion of the spark plug inside of the cylinder. This may be caused by the following conditions

1. Oil getting past worn piston rings
2. Breaking in a new or recently overhauled engine

Deposit fouling of the spark plug occurs when the normal reddish brown, yellow, or white deposits of combustion by-products become sufficient enough to cause misfiring. In some cases, these deposits melt and form a shiny glaze on the insulator around the center electrode. If the fouling is found only in one or two of the cylinders, valve stem clearances or the intake valve seals may be allowing excess lubricating oil to enter the cylinder, particularly if the deposits are heavier on the intake valve side of the spark plug.

Excess gap means that the air space between the center and side electrodes at the bottom of the spark plug is too wide for consistent firing. This may be due to improper gap adjustment or to excess wear of the electrodes during use. A gap that is too small may cause idling instability. Excess gap wear might indicate vehicle operation at continual high speeds or with high engine loads. This causes the spark plugs to run too hot. Excessively lean fuel may also cause the wear.

Improper torque or seating can cause a spark plug to run hot, eventually leading to excess gap wear. In extreme cases, an overtightened or under-tightened spark plug can cause exhaust blow-by. The cylinder head seats must make good contact for sufficient heat transfer and spark plug cooling. Dirty or damaged threads in the head or on the spark plug can keep the spark plug from seating even though the proper torque is applied. Once the spark plugs are properly seated, tighten the spark plugs properly.

Cracked or broken insulators and insulator tips may be the result of improper installation or heat shock. Heat shock is a rapid increase in the insulator tip temperature which causes the insulator material to crack. The upper insulators can be broken when a poorly-fitting tool is used during servicing, or when the spark plug is hit from the outside. Cracks in the upper insulator may be inside the shell or invisible. The breakage may not cause problems until oil or water penetrates the crack later. Heat shock breakage in the lower insulator tip generally occurs during severe engine operating conditions such as higher RPM or heavy loading. Over advanced timing or low grade fuels may also cause heat shock breakage. Always replace spark plugs with broken or cracked insulators.

Damage during gapping can occur when the tool is pushed against the center electrode or the surrounding insulator, causing the insulator to crack. When gapping a spark plug, bend only the outside electrode. Keep tools free of any other parts.

Spark plugs with less than the recommended amount of service can sometimes be cleaned and regapped, then returned to service. If there is any doubt about the serviceability of a spark plug, replace the spark plug.

J 42068 Spark Plug Centering Sleeve. See Special Tools and Equipment .

1. Remove the ignition coils. Refer to «Ignition Coil(s) Replacement - Bank 1»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) and «Ignition Coil(s) Replacement - Bank 2»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
2. Clean the spark plug recess area with low pressure air.
3. Attach the J 42068 to the 3/4 extension in order to protect the spark plug socket from getting cocked and cracking the plugs insulator. See «Special Tools and Equipment»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
4. Remove the spark plugs from the cylinder heads.
5. Inspect the spark plugs. Refer to «Spark Plug Inspection»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

1. Measure the spark plug gap on the spark plugs to be installed. Compare the measurement to the gap specifications. Refer to «Ignition System Specifications»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction__ignition-system-specifications) , correct as necessary.
2. Install the spark plugs to the cylinder heads. Tighten: Tighten the spark plugs to 25 N.m (18 lb ft).
3. Install the ignition coils. Refer to «Ignition Coil(s) Replacement - Bank 1»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) and «Ignition Coil(s) Replacement - Bank 2»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

Scheme 167

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/cts/i-2002-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the bolt securing the crankshaft position (CKP) sensor to the engine block.
3. Remove the CKP sensor and O-ring seal from the engine block.
4. Lower the vehicle.
5. Remove the following components depending on the RPO code in order to gain access to the CKP sensor pigtail: (LHD) The wiper motor module. Refer to «Wiper Motor Module Replacement (LHD)»(/cadillac/cts/i-2002-2007/remont/wiperwasher-systems/#wiper-system-and-washer-system) or «Wiper Motor Module Replacement (RHD)»(/cadillac/cts/i-2002-2007/remont/wiperwasher-systems/#wiper-system-and-washer-system) in Wipers/Washer Systems. (RHD) The left air inlet grill panel only. Refer to «Air Inlet Grille Panel Replacement (LHD)»(/cadillac/cts/i-2002-2007/remont/exterior-body-panels/#body-front-end) or «Air Inlet Grille Panel Replacement (RHD)»(/cadillac/cts/i-2002-2007/remont/exterior-body-panels/#body-front-end) in Body Front End. The front air inlet panel assembly bolts. The front air inlet panel assembly.
6. Disconnect the wiring harness connector from the CKP sensor pigtail (1).
7. Disconnect the CKP sensor pigtail (1) from the retainer.
8. Cut the tie strap securing the CKP sensor pigtail to the oil cooler pipes
9. Securely attach a scrap piece of wire about 91 cm (36 in) long to the CKP sensor pigtail. Later, this piece will be used as a pull wire to guide the new sensor pigtail back through the same routing.
10. Remove the CKP sensor pigtail. Observe the routing of the pigtail. Gently pull the CKP sensor pigtail down through the routing path and out.
11. Disconnect the sensor from the pull wire.

1. Securely attach the CKP sensor pigtail to the lower end of the pull wire.
2. Use the pull wire as a guide in order to pull the sensor pigtail up through the routing path into position.
3. Disconnect the pull wire from the sensor pigtail.
4. Connect the CKP sensor pigtail (1) to the retainer.
5. Connect the CKP sensor pigtail (1) to the wiring harness connector.
6. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/cts/i-2002-2007/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
7. Thoroughly clean the mating surfaces of the CKP sensor and the engine block.
8. Install the CKP sensor with a new O-ring seal into the engine block.
9. Install the bolt securing the CKP sensor to the engine block. Tighten: Tighten the CKP sensor bolt to 8 N.m (71 lb in).
10. Check the harness for proper routing. Do not allow the wiring to come in contact with the exhaust manifold.
11. Lower the vehicle.
12. Secure the CKP sensor pigtail to the oil cooler pipes using a tie strap.
13. Install the following components depending on the RPO code: (LHD) The wiper motor module. Refer to «Wiper Motor Module Replacement (LHD)»(/cadillac/cts/i-2002-2007/remont/wiperwasher-systems/#wiper-system-and-washer-system) or «Wiper Motor Module Replacement (RHD)»(/cadillac/cts/i-2002-2007/remont/wiperwasher-systems/#wiper-system-and-washer-system) in Wipers/Washer Systems. (RHD) The front air inlet panel assembly. The front air inlet panel assembly bolts. Tighten: Tighten the front air inlet panel assembly bolts to 6 N.m (53 lb in). The left air inlet grill panel. Refer to «Air Inlet Grille Panel Replacement (LHD)»(/cadillac/cts/i-2002-2007/remont/exterior-body-panels/#body-front-end) or «Air Inlet Grille Panel Replacement (RHD)»(/cadillac/cts/i-2002-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.

1. Disconnect the electrical connector from the camshaft position (CMP) sensor pigtail.
2. Remove the knock sensor (KS) pigtail retaining clip from the CMP sensor.
3. Remove the bolt securing the CMP sensor to the camshaft bearing cap.
4. Remove the CMP sensor from the camshaft bearing cap.

1. Thoroughly clean the mating surfaces of the CMP sensor and the camshaft bearing cap.
2. Install the CMP sensor into the camshaft bearing cap.
3. Install the bolt securing the CMP sensor to the camshaft bearing cap. Tighten: Tighten the CMP sensor bolt to 8 N.m (71 lb in).
4. Attach the KS pigtail retaining clip to the CMP sensor.
5. Connect the electrical connector to the CMP sensor pigtail.

1. Disconnect the knock sensor pigtail (1) from the electrical connector (2) and bracket.
2. Remove the generator. Refer to «Generator Replacement (LA3, LY9)»(/cadillac/cts/i-2002-2007/remont/charging-system/#battery-charging-system-and-starting-system) or «Generator Replacement (LS6)»(/cadillac/cts/i-2002-2007/remont/charging-system/#battery-charging-system-and-starting-system) or «Generator Replacement (LY7)»(/cadillac/cts/i-2002-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
3. Remove the knock sensor pigtail from the retaining clips on the rear timing belt cover.
4. Remove the bolt in the center of the knock sensor (1).
5. Remove the knock sensor (1) from the engine block.

1. Thoroughly clean the mating surfaces of the knock sensor and the engine block. The entire contact surface of the knock sensor must lie directly on the engine block.
2. Install the knock sensor (1) on to the engine block. Tighten: Tighten the knock sensor bolt to 20 N.m (15 lb ft).
3. Install the knock sensor pigtail into the retaining clips. Ensure that the pigtail does not contact any moving parts.
4. Install the generator. Refer to «Generator Replacement (LA3, LY9)»(/cadillac/cts/i-2002-2007/remont/charging-system/#battery-charging-system-and-starting-system) or «Generator Replacement (LS6)»(/cadillac/cts/i-2002-2007/remont/charging-system/#battery-charging-system-and-starting-system) or «Generator Replacement (LY7)»(/cadillac/cts/i-2002-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
5. Connect the knock sensor pigtail (1) to the knock sensor pigtail (2) and bracket.

1. Disconnect the knock sensor pigtail (1) from the electrical connector (2) and bracket.
2. Remove the accessory mounting bracket. Refer to «Accessory Mounting Brackets Replacement»(/cadillac/cts/i-2002-2007/remont/mechanical/#engine-mechanical-32l) in Engine Mechanical-2.6L and 3.2L.
3. Remove the knock sensor pigtail from the retaining clips.
4. Remove the bolt from the center of the knock sensor (2).
5. Remove the knock sensor (2) from the engine block.

1. Thoroughly clean the mating surfaces of the knock sensor and the engine block. The entire contact surface of the knock sensor must lie directly on the engine block.
2. Install the knock sensor (2) on to the engine block. Tighten: Tighten the knock sensor bolt to 20 N.m (15 lb ft).
3. Install the knock sensor pigtail into the retaining clips. Ensure that the pigtail does not contact any moving parts.
4. Install the accessory mounting bracket. Refer to «Accessory Mounting Brackets Replacement»(/cadillac/cts/i-2002-2007/remont/mechanical/#engine-mechanical-32l) in Engine Mechanical-2.6L and 3.2L.
5. Connect the knock sensor pigtail (1) to the electrical connector (2) and bracket.

1. Disconnect the air intake duct hose from the Mass Air Flow (MAF)/Intake Air Temperature (IAT) sensor.
2. Remove the bolt securing the intake air resonator to the cooling fan assembly.
3. Disconnect the air intake duct hoses from the throttle body.
4. Lift the intake air resonator from the front frame in order to access the electrical connector and vacuum hoses.
5. Disconnect the electrical connector from the intake resonance switchover solenoid.
6. Disconnect the vacuum hoses from the following components: The coolant bypass solenoid The intake plenum switchover solenoid The vacuum brake booster hose
7. Carefully position aside the following while removing the intake air resonator from the vehicle: The surge tank inlet hose The upper radiator hose

1. Carefully position aside the following while installing the intake air resonator in the engine compartment: The surge tank inlet hose The upper radiator hose
2. Route the vacuum hoses as previously noted.
3. Connect the vacuum hoses to the following components: The coolant bypass solenoid The intake plenum switchover solenoid The vacuum brake booster hose
4. Connect the electrical connector to the intake resonance switchover solenoid.
5. Insert the intake air resonator guide pins into the rubber mounts located in the front frame.
6. Connect they air intake duct hoses to the throttle body.
7. Install the bolt securing the intake air resonator to the cooling fan assembly. Tighten: Tighten the intake air resonator retaining bolt to 9 N.m (80 lb in).
8. Connect the air intake duct hose to the MAF/IAT sensor.

1. Disconnect the following from the intake plenum switchover solenoid (2): The electrical connector (1) The vacuum hoses
2. Remove the intake plenum switchover solenoid bolts.
3. Remove the intake plenum switchover solenoid from the intake plenum.

1. Position the intake plenum switchover solenoid to the intake plenum.
2. Install the intake plenum switchover solenoid bolts. Tighten: Tighten the intake plenum switchover solenoid bolts to 8 N.m (71 lb in).
3. Connect the following to the (2): The electrical connector (1) The vacuum hoses

1. Remove the intake plenum. Refer to «Intake Plenum Replacement»(/cadillac/cts/i-2002-2007/remont/mechanical/#engine-mechanical-32l) in Engine Mechanical-2.6L and 3.2L.
2. Disconnect the vacuum hose from the intake plenum switchover valve.
3. Remove the intake plenum switchover valve bolts.
4. Remove the intake plenum switchover valve and O-ring seal from the intake plenum. Discard the O-ring seal.

1. Install the intake plenum switchover valve with O-ring seal into the intake plenum.
2. Install the intake plenum switchover valve bolts. Tighten: Tighten the intake plenum switchover valve bolts to 8 N.m (71 lb in).
3. Connect the vacuum hose to the intake plenum switchover valve.
4. Install the intake plenum. Refer to «Intake Plenum Replacement»(/cadillac/cts/i-2002-2007/remont/mechanical/#engine-mechanical-32l) in Engine Mechanical-2.6L and 3.2L.

1. Remove the intake air resonator. Refer to «Intake Air Resonator Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
2. Disconnect the vacuum hose from the intake resonance switchover valve.
3. Remove the bolts securing the intake resonance switchover valve in the intake air resonator.
4. Remove the intake resonance switchover valve and O-ring from the intake air resonator. Discard the O-ring.

1. Install the switchover valve and O-ring into the intake air resonator.
2. Install the intake resonance switchover valve bolts. Tighten: Tighten the intake resonance switchover valve bolts to 8 N.m (71 lb in).
3. Connect the vacuum hose to the intake resonance switchover valve.
4. Install the intake air resonator. Refer to «Intake Air Resonator Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

1. Disconnect the following from the intake resonance switchover solenoid: The electrical connector IMPORTANT: Observe the proper positions of the vacuum hoses. The vacuum hoses
2. Remove the intake resonance switchover solenoid screws.
3. Remove the intake resonance switchover solenoid from the intake air resonator.

1. Position the intake resonance switchover solenoid to the intake air resonator.
2. Install the intake resonance switchover solenoid screws. Tighten: Tighten the intake resonance switchover solenoid screws to 3 N.m (27 lb in).
3. Connect the following to the intake resonance switchover solenoid: The electrical connector IMPORTANT: Properly position the vacuum hoses as previously noted during removal. The vacuum hoses

Scheme 168

1. Loosen the 2 screws located at the top of the air cleaner assembly.
2. Separate the 2 air cleaner assembly halves.
3. Lift the air cleaner element from the assembly.
4. Reset the air cleaner element indicator, by pushing upward from the bottom.

1. Clean out all traces of dirt and other contaminants from the air cleaner base and lid.
2. Place the air cleaner element between the assembly halves with the 2 locating tabs positioned down.
3. Join the 2 air cleaner assembly halves.
4. Tighten the 2 air cleaner element screws. Tighten: Tighten the air cleaner element screws to 8 N.m (71 lb in).

1. Remove the mass air flow (MAF)/intake air temperature (IAT) sensor. Refer to «Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .
2. Remove the 3 bolts securing the air cleaner assembly to the shock tower and upper tie bar.
3. Remove the air cleaner assembly from the vehicle.

1. Position the air cleaner assembly into the engine compartment.
2. Install the 3 bolts securing the air cleaner assembly to the shock tower and upper tie bar. Tighten: Tighten the air cleaner assembly bolts to 9 N.m (80 lb in).
3. Install the mass air flow (MAF)/intake air temperature (IAT) sensor. Refer to «Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-26l-32l-introduction) .

Scheme 169

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

Throttle Actuator Control (TAC) Overview

The throttle actuator control (TAC) system uses vehicle electronics and components to calculate and control the position of the throttle blade. This eliminates the need for a mechanical cable attachment from the accelerator pedal to the throttle body. This system also performs the cruise control functions as well.

The TAC system components include, but are not limited to, the following

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

The APP sensors and the throttle body assembly provide inputs to the ECM to ensure accurate calculations and control of the TAC system.

Accelerator Pedal Position (APP) Sensor

The APP sensor is mounted on the accelerator pedal assembly. The APP is actually 2 individual APP sensors within 1 housing. These are 2 separate signal, low reference, and 5-volt reference circuits. The APP sensor 1 voltage increases as the accelerator pedal is depressed. The APP sensor 2 voltage also increases as the accelerator pedal is depressed, but the voltage range for sensor 2 is approximately half of sensor 1.

Throttle Body Assembly

The throttle body assembly consists of the throttle body, the throttle position (TP) sensors, and the throttle actuator motor. The throttle body functions similar to a conventional throttle body with the following exceptions

1. An electronic motor opens and closes the throttle valve.
2. There are 2 individual TP sensors within the throttle body assembly.

Two separate signal circuits are used to connect the TP sensors and the ECM. The TP sensor 1 signal voltage increases as the throttle opens. The TP sensor 2 signal voltage decreases as the throttle opens.

Electronic Control Module (ECM)

The TAC module is the control center for the electronic throttle system. The TAC module is located within the ECM and is not serviceable separately. The ECM monitors the commanded throttle position and compares it to the actual throttle position. This is accomplished by monitoring the APP, TP, and other various sensors.

Reduced Engine Power Mode

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

1. Limited torque
2. Limited range of throttle movement
3. Engine OFF

Scheme 170

The fuel tank stores the fuel supply. The electric fuel pump supplies fuel through an in-line fuel filter 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 pressure regulator maintains the correct fuel pressure to the fuel injection system. A separate pipe (2) returns unused fuel to the fuel tank. The electric fuel pump (10) also supplies fuel to the siphon jet pump. The siphon jet pump (13) is attached to the right fuel tank module (11). The siphon jet pump draws fuel from the left side (4) of the fuel tank though the fuel transfer tube (5) to the right side of the fuel tank. Fuel is then equalized between the right and left sides of the tank.

Fuel Tank

The fuel storage tank is made of high density polyethylene and is located behind the rear wheels. The fuel storage tank is held in place by two metal straps that are attached to the under body of the vehicle. The tank shape includes a sump in order to maintain a constant supply of fuel around the fuel pump strainer during low fuel conditions or during aggressive maneuvers.

The tank also contains a fuel vapor vent valve with a roll-over protection. The vent valve also features a two phase vent calibration which increases the fuel vapor flow to the canister when the operating temperatures increase the tank pressure beyond an established threshold.

Fuel Tank Filler Pipe

In order to prevent refueling with leaded fuel, the fuel filler pipe has a built-in restrictor and a deflector. The opening in the restrictor will accept only the smaller unleaded gasoline fuel nozzle which must be fully inserted in order to bypass the deflector. The tank is vented during filling by an internal vent tube inside of the filler pipe.

Fuel Filler Cap

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 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.

Fuel Tank Module Assembly (Right)

A fuel tank module assembly is located in each side of the fuel tank. The fuel tank module assembly attaches to the upper side of the fuel tank. The right fuel tank module assembly consists of the following major components

1. Fuel level sensor
2. Electric fuel pump and reservoir bucket
3. Fuel pump strainer
4. Siphon jet pump

Fuel Tank Module Assembly (Left)

The assembly mounts to the threaded opening of the plastic fuel tank with a multi-lipped seal and a threaded retainer (nut). The assembly contains the following

1. Fuel level sensor
2. Fuel sender strainer

Fuel Pump

The electric fuel pump is a turbine pump which is located inside of the fuel tank module assembly (right). The electric fuel pump operation is controlled by the engine control module (ECM) through the fuel pump relay.

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.

Scheme 171

The fuel filter is located on the fuel feed pipe between the fuel pump and the fuel rail. The electric fuel pump supplies fuel through the in-line fuel filter to the Fuel Injection System. The fuel pressure regulator keeps the fuel available to the fuel injectors at a regulated pressure. Unused fuel is returned from the fuel filter to the fuel tank by a separate fuel return pipe. The paper filter element (2) traps particles in the fuel that may damage the Fuel Injection System. The filter housing (1) 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. Replace a restriction fuel filter.

Fuel Lines and Return Pipes

The fuel feed pipe carries fuel from the fuel tank to the fuel rail assembly. The fuel return pipe carries fuel from the fuel rail assembly back to the fuel tank. The fuel pipes consist of 2 sections

1. The rear fuel pipe assemblies are located from the top of the fuel tank to the chassis fuel pipes. The rear fuel pipes are constructed of nylon.
2. The chassis fuel pipes are located under the vehicle and connect the rear fuel pipes to the fuel rail pipes. These pipes are constructed of steel.

Scheme 172

The fuel rail consists of 4 parts

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

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

The fuel is delivered from the pump through the fuel feed line to the inlet port of the fuel rail pipe. From the fuel feed inlet, fuel is directed to the rail pipe to the fuel pressure regulator. Any fuel in excess of the injector needs will flow back through the pressure regulator assembly to the outlet port of the fuel rail. The fuel then flows through the fuel return line to the fuel tank to begin the cycle again.

Fuel Injectors

The fuel injector is a solenoid device that is controlled by the 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 or high coil resistance

Scheme 173

The fuel pressure regulator attaches to the fuel return pipe on the fuel sender assembly. The fuel pressure regulator is a diaphragm-operated relief valve. A software bias compensates the injector on-time because the fuel pressure regulator is not referenced to manifold vacuum. The injector pulse width varies with the signal from the MAF/IAT sensor. With the engine running at idle, the system fuel pressure at the pressure test connection should be between 380-410 kPa (55-60 psi). With the system pressurized and the pump OFF the pressure should stabilize and hold. If the pressure regulator supplies a fuel pressure which is too low or too high, a driveability condition will result.

Fuel Pump Relay

When the ignition switch is in the ON position before engaging the starter, the ECM energizes the fuel pump relay for 2 seconds, causing the fuel pump to pressurize the fuel system. If the ECM does not receive the ignition, reference pulses with the engine cranking or running within 2 seconds, the ECM shuts OFF the fuel pump relay, causing the fuel pump to stop.

Engine Fueling

The engine is fueled by six individual injectors, one for each cylinder, that are controlled by the 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 control module 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 stringent conditions, the fueling system will not energize the injectors, individually or in groups, for a period of time. This is referred to as the fuel shut-off. The fuel shut-off is used in order to improve the traction, save fuel, improve the starting, and protect the vehicle under certain extreme or abusive conditions.

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

Sequential Multiport Fuel Injection

The 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 a sequential multiport 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 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 ECM will reduce fuel flow to the injectors and will maintain this stage as long as the ECM indicates a WOT condition with engine speed below 1,000 RPM.

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 above 480 RPM, the system goes into an Open Loop operation. In an Open Loop operation, the 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 a 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 ECM monitors the changes in the throttle position (TP) and the MAF sensor J 41398 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 driveability.

Deceleration Mode

The ECM monitors changes in TP and 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.

Battery Voltage Correction Mode

The 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 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 ignition reference 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. The extended high speed closed throttle coastdown-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 solenoid to the atmosphere. The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the control module will command the EVAP purge solenoid ON, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent solenoid OFF, fresh air is drawn through the vent solenoid and the vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge solenoid 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 commands the EVAP vent solenoid ON and commands the EVAP purge solenoid ON, with the engine running, allowing engine vacuum into the EVAP system. The control module monitors the fuel tank pressure (FTP) sensor voltage to verify that the system is able to reach a predetermined level of vacuum within a set amount of time. The control module then commands the EVAP purge solenoid OFF, sealing the system, and monitors the vacuum level for decay. If the control module does not detect that the predetermined vacuum level was achieved, or the vacuum decay rate is more than a calibrated level on 2 consecutive tests, DTC P0455 will set.

Small Leak Test

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

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

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

Canister Vent Restriction Test

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

Purge Solenoid Leak Test

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

Check Gas Cap Message

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

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

EVAP System Components

The EVAP system consists of the following components

EVAP Canister

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

EVAP Purge Solenoid

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

EVAP Vent Solenoid

The EVAP vent solenoid controls fresh airflow into the EVAP canister. The solenoid is normally open. The control module commands the solenoid ON, closing the solenoid 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. A high FTP sensor voltage indicates a low fuel tank pressure or vacuum. A low FTP sensor voltage indicates a high fuel tank pressure.

EVAP Service Port

The EVAP service port is located in the EVAP purge pipe between the EVAP purge solenoid 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 and the driver modules are contained within two assemblies, one for each cylinder bank. The assemblies are mounted in the center of each camshaft cover with short boots connecting 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 and position information from the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor. This controls the sequence, dwell, and timing of the spark. The EI system consists of the components listed below.

Crankshaft Position (CKP) Sensor

The CKP sensor is a permanent magnet generator, known as a variable reluctance sensor. The sensor is mounted in the left rear of the cylinder block. A crankshaft mounted reluctor wheel that has sixty slots, two of which are missing, alters the magnetic field of the sensor. This arrangement results in the CKP sensor output of fifty-eight pulses per crankshaft revolution. The two missing slots represent the position of the cylinder 1 and cylinder 4 pistons 84 degrees before top dead center (BTDC). The CKP sensor is connected to the ECM by a signal circuit and a low reference circuit. Both CKP sensor circuits are protected from electromagnetic interference by a shielding ground circuit. The shielding circuit is grounded through the ECM. Using the CKP signals in conjunction with those from the CMP sensor the ECM determines the engine position with great accuracy.

Camshaft Position (CMP) Sensor

The CMP sensor signal is a digital ON/OFF pulse, output once 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 ECM to determine the position of the valve train relative to the crankshaft. By monitoring the CMP and CKP signals the ECM can accurately time the operation of the fuel injectors. The ECM supplies the CMP sensor with a 12-volt reference circuit and a low reference circuit. The CMP sensor signal is an input to the ECM. The CMP is protected from electromagnetic interference by the same shielding circuit used by the CKP sensor.

Ignition Coils

The Ignition System uses a ignition coil assembly for each bank. Each ignition coil assembly consist of 3 ignition coils. The ignition coil assemblies consist of the following circuits

1. An ignition voltage circuit
2. A ground circuit
3. An ignition control (IC) circuit for each ignition coil

The ignition coil assemblies are mounted in the center of each camshaft cover with short boots connecting the coils to the spark plugs. The engine control module (ECM) primarily uses engine speed and position information from the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor to control the sequence, dwell, and timing of the spark. The ECM can command each ignition coil ON/OFF by grounding the IC circuit of the ignition coil. The IC circuits are pulse width modulated (PWM) in order to precisely control the spark events.

Engine Control Module (ECM)

The 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)

Modes of Operation

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

Scheme 174

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

The control module reads the voltage of the sensor during the 45 degrees after cylinder 2, 4, or 6 has fired and the voltage of the sensor during the 45 degrees after cylinder 1, 3, or 5 has fired.

If knock occurs in any of the cylinders, the ignition will be retarded by 3 degrees for that particular cylinder. If the knocking then stops, the ignition will be restored to what it was before in steps of 0.75 degrees.

Should knocking continue in the same cylinder in spite of the ignition being retarded, the control module will retard the ignition an additional step of 3 degrees, and so on, up to a maximum of 12.75 degrees. The ignition will also be retarded at high ambient temperatures in order to counteract knocking tendencies provoked by high intake air temperatures.

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Scheme 176

The multi-ram system functional diagram shows four stages of air flow

1. I is air flow at idle
2. II is air flow at full load, low RPM
3. III is air flow at full load, mid RPM
4. IV is air flow at full load, high RPM

The characteristic torque curve of a normally aspirated engine depends mainly on how the engines average pressure changes over the RPM 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 sucked into a cylinder at a given engine RPM.

Thus, the air intake system determines the engines torque curve. A longer intake manifold results in higher torque at lower RPM, and a shorter intake manifold results in higher torque at higher RPM.

The intake manifold on this engine is fitted with 2 valves which can be set for 4 different intake manifold lengths. The 4 different manifold lengths obtainable result in different torque curves with maximum torque at different engine RPM. The intake plenum switchover valve (1) is located in the intake manifold between the cylinder heads. The intake resonance switchover valve (2) is located between the 2 resonating pipes connected to the intake manifold. The control module controls the 2 valves by means of solenoid valves and vacuum operated diaphragm units. The solenoid valves are supplied with current via the main relay and are grounded by the control module. When the control module enables the solenoid for the intake plenum swithover valve, the valve opens and connects the inlet systems of the two banks of cylinders to each other. When the control module enables the solenoid for the intake resonance switchover valve, the valve opens a connection between the 2 resonating pipes and the active length of the pipes are thus reduced.

During wide-open throttle (WOT) acceleration from low RPM, the control module disables the intake plenum switchover valve. This separates the cylinder banks from each other and connects each of them to its own resonating pipe. With the intake resonance switchover valve now closed, the full length of the resonating pipes is utilized.

When the engine speed reaches 3,200 RPM, the control module enables the solenoid for the intake resonance switchover valve. This causes the valve to open and connect 2 resonating pipes, so their active length is reduced.

When engine speed reaches 4,100 RPM, the control module enables the circuit to the intake plenum switchover valve, so that the 2 inlet systems, 1 for each bank of cylinders, are connected to each other, and the effective pipe length is the shortest possible.

Using this system allows the torque curves to overlap in a way that produces the most favorable results.

At speeds below 4,100 RPM and with a throttle valve angle less than 50 percent, the intake plenum switchover valve is always open. This keeps the idle air control (IAC) valves supplementary air distributed equally between the cylinders.

Special Tools

Special Tools Illustration Tool Number/Description J 23738-A Vacuum Pump J 26792 Spark Tester J 34142-B Unpowered Test Light J 34730-1A Fuel Pressure Gage J 34730-2C TBI Harness Test Lamp J 34730-405 Injector Test Lamp J 35616-A Connector Test Adapter Kit J 36012-A Ignition System Diagnosis Harness J 36850 Transjel Lubricant J 37088-A Fuel Line Disconnect Tool Set J 37287 Fuel Line Shut-Off Adapters J 37287-100 Fuel Line Shut-Off Quick Connect Adapters J 39021 Fuel Injector Coil/Balance Tester J 39021-210 Injector Tester Adapter Box J 39021-360 Fuel Injector Test Adapter J 39194 Oxygen Sensor Wrench J 39200 Digital Multimeter (DMM) J 41413-200 Evaporative Emission System Tester (EEST) J 41413-SPT High Intensity White Light J 41413-VLV EVAP Service Port Fitting J 41415-40 Fuel Tank Cap Adapter J 41416 Ultrasonic Leak Detector J 42068 Spark Plug Centering Sleeve J 42242 Fuel Pressure Gage Adapter J 42960-2 Fuel Flapper Door Holder J 43301 Coil Pack Remover J 44175 Fuel Composition Tester J 44581 Fuel Line Disconnect Tool J 45004 Fuel Drain Hose J 45289 CANdi Module J 45747 Fuel Tank Sender Wrench 70000081 Tech II Scan Tool

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See also:
• Fastener Notice
• Service Programming System (SPS)
• Programming Theft Deterrent System Components
• Draining and Filling Cooling System (LA3, LY9)
• Wiper Motor Module Replacement (LHD)
• Component Fastener Tightening Notice
• Lifting and Jacking the Vehicle
• Oxygen Sensor Notice
• Closeout/Insulator Panel Replacement - Left
• Gasoline/Gasoline Vapors Caution
• Battery Negative Cable Disconnect/Connect Procedure
• Exhaust System Replacement (LA3, LY9)
• Exhaust System Replacement (LY7)
• Exhaust System Replacement (LS6)
• Propeller Shaft Replacement (Automatic Transmission)
• Fuel Tank Leak Test
• Tire and Wheel Removal and Installation
• Fascia Extension Replacement - Rear
• Air Inlet Grille Panel Replacement (LHD)
• Intake Plenum Replacement
• Frame Replacement - Rear
• Idle Learn Procedure
• Special Tools and Equipment
• Fuel Pressure Relief Procedure
• Quick Connect Fitting(s) Service (Metal Collar)
• Fuel Tank Replacement
• Fuel Filter Replacement
• Ignition System Specifications