Temperature vs Resistance - Engine Coolant Temperature (ECT) Sensor
| Temperature C°/F° | Resistance Minimum Ohms | Resistance Maximum Ohms |
|---|---|---|
| Engine Coolant Temperature (ECT) | ||
| 40/-40 | 40,490 | 50,136 |
| 20/-4 | 14,096 | 16,827 |
| 10/14 | 8,642 | 10,152 |
| 0/32 | 5,466 | 6,326 |
| 20/68 | 2,351 | 2,649 |
| 25/77 | 1,941 | 2,173 |
| 40/104 | 1,118 | 1,231 |
| 60/140 | 573 | 618 |
| 80/176 | 313 | 332 |
| 100/212 | 182 | 191 |
| 120/248 | 109 | 116 |
| 140/284 | 068 | 074 |
Temperature vs Resistance - Engine Coolant Temperature (ECT) Sensor
Temperature vs Resistance - Intake Air Temperature (IAT) Sensor
| Temperature C°/F° | Resistance Minimum Ohms | Resistance Maximum Ohms |
|---|---|---|
| Intake Air Temperature (IAT) Sensor | ||
| 40/-40 | 35,140 | 43,760 |
| 20/-4 | 12,660 | 15,120 |
| 10/14 | 7,943 | 9,307 |
| 0/32 | 5,119 | 5,892 |
| 20/68 | 2,290 | 2,551 |
| 25/77 | 1,900 | 2,100 |
| 40/104 | 1,096 | 1,238 |
| 60/140 | 565 | 654 |
| 80/176 | 312 | 370 |
| 100/212 | 184 | 222 |
| 120/248 | 114 | 141 |
| 140/284 | 74 | 93 |
Temperature vs Resistance - Intake Air Temperature (IAT) Sensor
Ignition System Specifications
| Application | Specification | |
|---|---|---|
| Metric | English | |
| Firing Order | 1-2-3-4-5-6 | |
| Spark Plug Gap (non-adjustable) | 1.10 mm | 0.044 in |
| Spark Plug Torque | 20 N.m | 15 lb ft |
| Spark Plug Type | AC 41-988 | |
Ignition System Specifications
Fastener Tightening Specifications
| Application | Specification | |
|---|---|---|
| Metric | English | |
| Accelerator Pedal Position (APP) Sensor Bolt | 10 N.m | 89 lb in |
| Air Cleaner Bolt | 10 N.m | 89 lb in |
| Air Cleaner Inlet Duct Clamp | 6 N.m | 53 lb in |
| Air Cleaner Upper Cover Bolt | 4 N.m | 35 lb in |
| Barometric Pressure Sensor Bolt | 10 N.m | 89 lb in |
| Camshaft Position Actuator Valve | 10 N.m | 89 lb in |
| Camshaft Position (CMP) Sensor Bolt | 10 N.m | 89 lb in |
| Crankshaft Position (CKP) Sensor Bolt | 10 N.m | 89 lb in |
| ECM Bolts | 10 N.m | 89 lb in |
| ECM Bracket Bolt | 10 N.m | 89 lb in |
| ECM Redundant Ground Wire Bolt (at Cylinder Head) | 10 N.m | 89 lb in |
| ECM Redundant Ground Wire Screw (at ECM) | 4 N.m | 35 lb in |
| Engine Coolant Temperature (ECT) Sensor | 22 N.m | 16 lb ft |
| EVAP Canister Bracket Nut (at Chassis) | 6 N.m | 53 lb in |
| EVAP Canister Bracket Nut (at Tank) | 10 N.m | 89 lb in |
| EVAP Canister Purge Valve Bolt | 10 N.m | 89 lb in |
| Fuel Filler Pipe Bolt | 25 N.m | 18 lb in |
| Fuel Filler Pipe Hose Clamp | 2.5 N.m | 22 lb in |
| Fuel Filler Pipe Nut | 6 N.m | 53 lb in |
| Fuel Rail Bolt | 10 N.m | 89 lb in |
| Fuel Tank Strap Bolt | 47 N.m | 35 lb ft |
| Heated Oxygen Sensor (HO2S) | 42 N.m | 31 lb ft |
| Ignition Coil Bolt | 10 N.m | 89 lb in |
| Intake Manifold Runner Control Solenoid Bolt | 10 N.m | 89 lb in |
| Knock Sensor Bolt | 23 N.m | 17 lb ft |
| Knock Sensor Electrical Connector Bracket Bolt (Bank 1) | 65 N.m | 48 lb ft |
| MAF Sensor Screw | 4 N.m | 35 lb in |
| Spark Plug | 20 N.m | 15 lb ft |
| Throttle Body Bolt | 10 N.m | 89 lb in |
Fastener Tightening Specifications
Action Taken When the DTC Sets - Type A
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
Action Taken When the DTC Sets - Type B
The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.
Action Taken When the DTC Sets - Type B1
- The following applies to misfire DTCs: If the control module detects a low level or an emission level misfire condition during 2 consecutive trips, the control module illuminates the MIL. If the control module detects a high level or catalyst damaging misfire, the control module flashes the MIL at a rate of once per second. If the control module detects a misfire during 2 non-consecutive trips, the stored conditions are compared with the current conditions. The control module illuminates the MIL when the following conditions occur: The engine load is within 10 percent of the previous test that failed. The engine speed is within 375 RPM of the previous test that failed. The engine coolant temperature is in the same range of the previous test that failed.
- The following applies to fuel trim DTCs: If the control module detects a fuel trim condition during 2 consecutive trips, the control module illuminates the MIL. If the control module detects a fuel trim condition during 2 non-consecutive trips, the stored conditions are compared with the current conditions. The control module illuminates the MIL when the following conditions occur: The engine load is within 10 percent of the previous test that failed. The engine speed is within 375 RPM of the previous test that failed. The engine coolant temperature is in the same range of the previous test that failed.
Conditions for Clearing the MIL/DTC - Type A or Type B
- The control module turns OFF the MIL after 3 or 4 consecutive ignition cycles depending on the DTC, when the diagnostic runs and does not fail.
- An active DTC clears when the diagnostic runs and passes.
- Use a scan tool in order to clear the MIL and the DTC.
Action Taken When the DTC Sets - Type C
- The control module stores the DTC information into memory when the diagnostic runs and fails.
- The MIL will not illuminate.
- The driver information center, if equipped, may display a message.
Conditions for Clearing the DTC - Type C
- A last test failed or active DTC, clears when the diagnostic runs and passes.
- Use a scan tool in order to clear the DTC.
Diagnostic Trouble Code (DTC) Type(s)
| DTC | United States, Canada and Mexico | Unleaded Export - RPO NA3, NT4, NT7, NT9 | Unleaded Export - RPO NF9 |
|---|---|---|---|
| P0008 | B | B | C |
| P0009 | B | B | C |
| P0010 | B | B | B |
| P0011 | B | B | B |
| P0013 | B | B | B |
| P0014 | B | B | B |
| P0016 | B | B | C |
| P0017 | B | B | C |
| P0018 | B | B | C |
| P0019 | B | B | C |
| P0020 | B | B | B |
| P0021 | B | B | B |
| P0023 | B | B | B |
| P0024 | B | B | B |
| P0030 | B | B | B |
| P0031 | B | B | B |
| P0032 | B | B | B |
| P0036 | B | B | B |
| P0037 | B | B | B |
| P0038 | B | B | B |
| P0053 | B | B | C |
| P0101 | B | B | C |
| P0102 | B | B | B |
| P0103 | B | B | B |
| P0112 | B | B | B |
| P0113 | B | B | B |
| P0117 | B | B | B |
| P0118 | B | B | B |
| P0121 | B | B | B |
| P0122 | B | B | B |
| P0123 | B | B | B |
| P0125 | B | B | C |
| P0128 | B | C | C |
| P0130 | B | B | B |
| P0131 | B | B | B |
| P0132 | B | B | B |
| P0133 | B | B | C |
| P0135 | B | B | C |
| P0137 | B | B | B |
| P0138 | B | B | B |
| P0140 | B | B | B |
| P0141 | B | B | C |
| P0201 | B | B | B |
| P0202 | B | B | B |
| P0203 | B | B | B |
| P0204 | B | B | B |
| P0205 | B | B | B |
| P0206 | B | B | B |
| P0221 | B | B | B |
| P0222 | B | B | B |
| P0223 | B | B | B |
| P0261 | B | B | B |
| P0262 | B | B | B |
| P0264 | B | B | B |
| P0265 | B | B | B |
| P0267 | B | B | B |
| P0268 | B | B | B |
| P0270 | B | B | B |
| P0271 | B | B | B |
| P0273 | B | B | B |
| P0274 | B | B | B |
| P0276 | B | B | B |
| P0277 | B | B | B |
| P0300 | B1 | B1 | C |
| P0301 | B1 | B1 | C |
| P0302 | B1 | B1 | C |
| P0303 | B1 | B1 | C |
| P0304 | B1 | B1 | C |
| P0305 | B1 | B1 | C |
| P0306 | B1 | B1 | C |
| P0318 | C | C | C |
| P0324 | B | B | B |
| P0327 | B | B | C |
| P0328 | B | B | C |
| P0332 | B | B | C |
| P0333 | B | B | C |
| P0335 | A | A | A |
| P0336 | A | A | A |
| P0338 | A | A | A |
| P0341 | B | B | B |
| P0342 | B | B | B |
| P0343 | B | B | B |
| P0346 | B | B | B |
| P0347 | B | B | B |
| P0348 | B | B | B |
| P0351 | B | B | B |
| P0352 | B | B | B |
| P0353 | B | B | B |
| P0354 | B | B | B |
| P0355 | B | B | B |
| P0356 | B | B | B |
| P0366 | B | B | B |
| P0367 | B | B | B |
| P0368 | B | B | B |
| P0391 | B | B | B |
| P0392 | B | B | B |
| P0393 | B | B | B |
| P0420 | B | B | C |
| P0442 | A | X | X |
| P0443 | B | B | B |
| P0446 | B | B | C |
| P0449 | B | B | B |
| P0451 | B | B | C |
| P0452 | B | B | B |
| P0453 | B | B | B |
| P0455 | B | B | C |
| P0458 | B | B | B |
| P0459 | B | B | B |
| P0461 | C | C | C |
| P0462 | C | C | C |
| P0463 | C | C | C |
| P0480 | B | B | B |
| P0481 | B | B | B |
| P0496 | B | B | C |
| P0498 | B | B | B |
| P0499 | B | B | B |
| P0506 | B | C | C |
| P0507 | B | C | C |
| P0521 | C | C | C |
| P0522 | C | C | C |
| P0523 | C | C | C |
| P0532 | C | C | C |
| P0533 | C | C | C |
| P0560 | C | C | C |
| P0562 | C | C | C |
| P0563 | C | C | C |
| P0567 | C | C | C |
| P0567 | C | C | C |
| P0567 | C | C | C |
| P0567 | C | C | C |
| P0568 | C | C | C |
| P0601 | A | A | A |
| P0602 | A | A | A |
| P0604 | A | A | A |
| P0606 | A | A | A |
| P0615 | C | C | C |
| P0616 | C | C | C |
| P0617 | C | C | C |
| P0625 | C | C | C |
| P0626 | C | C | C |
| P0627 | B | B | B |
| P0628 | B | B | B |
| P0629 | B | B | B |
| P0638 | A | A | A |
| P0645 | C | C | C |
| P0646 | C | C | C |
| P0647 | C | C | C |
| P0650 | B - No MIL | B - No MIL | B - No MIL |
| P0654 | C | C | C |
| P0685 | C | C | C |
| P0686 | C | C | C |
| P0687 | C | C | C |
| P0689 | C | C | C |
| P0690 | C | C | C |
| P0691 | B | B | B |
| P0692 | B | B | B |
| P0693 | B | B | B |
| P0694 | B | B | B |
| P0700 | A | A | A |
| P0850 | C | C | C |
| P0856 | C | C | C |
| P0864 | C | C | C |
| P1011 | C | C | C |
| P1012 | C | C | C |
| P1013 | C | C | C |
| P1014 | C | C | C |
| P1258 | A | A | A |
| P1551 | A | A | A |
| P1629 | C | C | C |
| P1630 | C | C | C |
| P1631 | C | C | C |
| P1668 | C | C | C |
| P167A | B | B | B |
| P1689 | C | C | C |
| P2088 | B | B | B |
| P2089 | B | B | B |
| P2090 | B | B | B |
| P2091 | B | B | B |
| P2092 | B | B | B |
| P2093 | B | B | B |
| P2094 | B | B | B |
| P2095 | B | B | B |
| P2096 | B | B | C |
| P2097 | B | B | C |
| P2100 | A | A | A |
| P2101 | A | A | A |
| P2105 | A | A | A |
| P2107 | C | C | C |
| P2119 | A | A | A |
| P2122 | A | A | A |
| P2123 | A | A | A |
| P2127 | A | A | A |
| P2128 | A | A | A |
| P2138 | A | A | A |
| P2176 | A | A | A |
| P2177 | B1 | B1 | C |
| P2178 | B1 | B1 | C |
| P2187 | B1 | B1 | C |
| P2188 | B1 | B1 | C |
| P2195 | B | B | C |
| P2196 | B | B | C |
| P2227 | B | B | C |
| P2228 | B | B | B |
| P2229 | B | B | B |
| P2231 | B | B | C |
| P2232 | B | B | B |
| P2237 | B | B | C |
| P2243 | B | B | C |
| P2251 | B | B | C |
| P2270 | B | B | C |
| P2271 | B | B | C |
| P2297 | B | B | C |
| P2300 | B | B | B |
| P2301 | B | B | B |
| P2303 | B | B | B |
| P2304 | B | B | B |
| P2306 | B | B | B |
| P2307 | B | B | B |
| P2309 | B | B | B |
| P2310 | B | B | B |
| P2312 | B | B | B |
| P2313 | B | B | B |
| P2315 | B | B | B |
| P2316 | B | B | B |
| P2626 | B | B | C |
| U0001 | A | A | A |
| U0101 | A | A | A |
| U1040 | C | C | C |
| U1064 | C | C | C |
| U1096 | C | C | C |
| U1192 | C | C | C |
| U1300 | C | C | C |
| U1301 | C | C | C |
Diagnostic Trouble Code (DTC) Type(s)
Scheme 1
| Callout | Component Name |
|---|---|
| 1 | Emissions Hose to Evaporative Emissions (EVAP) Canister |
| 2 | Positive Crankcase Ventilation (PCV) Hose to Cam Cover |
| 3 | Throttle Body Assembly |
| 4 | Upper Intake Manifold |
| 5 | EVAP Canister Purge Solenoid |
Scheme 2
| Callout | Component Name |
|---|---|
| 1 | Evaporative Emission (EVAP) Service Port Connection |
| 2 | EVAP Purge Solenoid |
| 3 | EVAP Purge Hose/Pipe |
| 4 | Fuel Tank |
| 5 | EVAP Purge Canister |
| 6 | Fuel Filler Pipe Vapor Recirculation Hose |
| 7 | Fill Limit Vent Valve (FLVV) |
| 8 | Fuel Tank Pressure (FTP) Sensor |
| 9 | EVAP Vapor Hose/Pipe from FLVV to Canister |
| 10 | EVAP Purge Hose/Pipe Connection to Canister |
| 11 | EVAP Hose/Pipe from Vent Valve Solenoid to Canister |
| 12 | Fuel Filler Pipe Vapor Recirculation Hose |
| 13 | Fuel Filler Cap |
| 14 | EVAP Vent Valve Solenoid |
Scheme 3
| Callout | Component Name |
|---|---|
| 1 | Fuel Pressure Test Connection |
| 2 | Fuel Rail Assembly |
| 3 | Fuel Tank |
| 4 | Fuel Sender Module Assembly |
| 5 | Fill Limit Vent Valve (FLVV) |
| 6 | Fuel Return Inlet - Not Used |
| 7 | Fuel Sender Module Electrical Connector |
| 8 | Fuel Feed Hose/Pipe Connection |
| 9 | Fuel Filler Pipe Vapor Recirculation Hose |
| 10 | Fuel Filler Pipe |
| 11 | Fuel Feed Hose/Pipe - Fuel Tank |
| 12 | Fuel Feed Hose/Pipe - Chassis |
Scheme 4
Scheme 5
Scheme 6
Scheme 7
Scheme 8
Scheme 9
Scheme 10
Scheme 11
Scheme 12
Scheme 13
Scheme 14
Scheme 15
Scheme 16
Scheme 17
Scheme 18
| Callout | Component Name |
|---|---|
| 1 | Ignition Coil 5 |
| 2 | Evaporative Emission (EVAP) Canister Purge Solenoid Valve |
| 3 | Ignition Coil 3 |
| 4 | Ignition Coil 1 |
| 5 | Throttle Body Assembly |
| 6 | Knock Sensor (KS) 1 |
| 7 | Crankshaft Position (CKP) Sensor |
| 8 | Engine Block Heater Assembly |
Scheme 19
| Callout | Component Name |
|---|---|
| 1 | Ignition Coil 2 |
| 2 | Ignition Coil 4 |
| 3 | Ignition Coil 6 |
| 4 | Engine Coolant Temperature (ECT) Sensor |
| 5 | Knock Sensor (KS) 2 |
| 6 | Engine Oil Level/Temperature Sensor |
| 7 | Engine Oil Pressure (EOP) Sensor |
Scheme 20
| Callout | Component Name |
|---|---|
| 1 | Camshaft Position (CMP) Sensor - Exhaust Bank 1 |
| 2 | Camshaft Position (CMP) Actuator Solenoid - Exhaust Bank 1 |
| 3 | Camshaft Position (CMP) Actuator Solenoid - Intake Bank 1 |
| 4 | Camshaft Position (CMP) Sensor - Intake Bank 1 |
| 5 | Camshaft Position (CMP) Sensor - Intake Bank 2 |
| 6 | Camshaft Position (CMP) Actuator Solenoid - Intake Bank 2 |
| 7 | Camshaft Position (CMP) Actuator Solenoid - Exhaust Bank 2 |
| 8 | Camshaft Position (CMP) Sensor - Exhaust Bank 2 |
Scheme 21
| Callout | Component Name |
|---|---|
| 1 | Fuel Tank |
| 2 | Fuel Tank Pressure (FTP) Sensor |
| 3 | C405 |
| 4 | Fuel Pump and Sender Assembly |
| 5 | Evaporative Emission (EVAP) Canister Vent Solenoid Valve |
| 6 | EVAP Canister |
Scheme 22
| Callout | Component Name |
|---|---|
| 1 | Electronic Control Module (ECM) C1 |
| 2 | Electronic Control Module (ECM) |
| 3 | Electronic Control Module (ECM) C2 |
Scheme 23
| Callout | Component Name |
|---|---|
| 1 | Air Cleaner Assembly |
| 2 | Manifold Absolute Pressure (MAP) Sensor |
| 3 | Engine Block |
Scheme 24
| Callout | Component Name |
|---|---|
| 1 | Catalytic Converter |
| 2 | Heated Oxygen Sensor (HO2S) 2 |
Scheme 25
| Callout | Component Name |
|---|---|
| 1 | Heated Oxygen Sensor (HO2S) 1 |
| 2 | Engine Valve Cover |
| 3 | Exhaust Manifold |
Scheme 26
| Callout | Component Name |
|---|---|
| 1 | Valve Cover - Right |
| 2 | Fuel Injector 5 |
| 3 | Intake Manifold |
| 4 | Fuel Injector 6 |
| 5 | Fuel Injector 4 |
| 6 | Fuel Injector 2 |
| 7 | Valve Cover - Left |
| 8 | Fuel Injector 1 |
| 9 | Fuel Injector 3 |
Engine Control Module (ECM) Connector End Views
Engine Control Module (ECM) C1 Connector Part Information OEM: 1 928 403 379 (Bosch) 10774745 (Delphi) Service: See Catalog 64-Way F (BK) Pin Wire Color Circuit No. Function 1 TN 407 KS Low Reference Bank 2 2 - - Not Used 3 L-GN 5278 HO2S Input Pump Current Sensor 1 4 OG 5275 CMP Sensor Signal - Intake Bank 1 5 GY 605 5-Volt Reference 6 - - Not Used 7 TN 470 Low Reference 8 PU 486 TP Sensor 2 Signal 9 D-GN/WH 2124 Ignition Control 4 10 WH/BK 5039 CKP Sensor Signal 11 - - Not Used 12 OG/BK 5272 CMP Actuator Solenoid Control - Intake Bank 2 13 L-GN 5282 CMP Actuator Solenoid Control - Exhaust Bank 1 14 - - Not Used 15 BN 582 TAC Motor Control - 2 16 GY/WH 3113 HO2S Heater Low Control Sensor 1 17 GY 1716 KS Low Reference Bank 1 18 - - Not Used 19 PU/WH 1665 HO2S High Signal 20 D- GN 5273 CMP Sensor Signal - Exhaust Bank 1 21 GY 23 Generator Field Duty Cycle Signal 22 - - Not Used 23 YE 410 ECT Sensor Signal 24 - - Not Used 25 L-BU/WH 2126 Ignition Control 6 26 OG/WH 2122 Ignition Control 2 27-28 - - Not Used 29 PU 5284 Actuator Solenoid Control - Intake Bank 1 30 WH/BK 5283 Actuator Solenoid Control - Exhaust Bank 2 31 YE 581 TAC Motor Control - 1 32 - - Not Used 33 D-BU 496 KS Signal Bank 1 34 - - Not Used 35 WH 5279 HO2S Pump Current 36 PU 5274 CMP Sensor Signal - Exhaust Bank 2 37 BN 1174 Oil Level Switch Signal 38 D-GN/WH 357 Oil Temperature Sensor Signal 39 TN 2752 Low Reference 40 TN/BK 231 Engine Oil Pressure Switch Signal 41 D-GN 2125 Ignition Control 5 42 PU 2121 Ignition Control 1 43 OG 225 Generator Turn On Signal 44 - - Not Used 45 L-BU/BK 844 Fuel Injector 4 Control 46 PK/BK 1746 Fuel Injector 3 Control 47 TN/WH 845 Fuel Injector 5 Control 48 D-GN/WH 428 EVAP Canister Purge Solenoid Valve Control 49 GY/BK 1798 Ground 50 L-BU 1876 KS Signal Bank 2 51 - - Not Used 52 TN 1664 HO2S Low Signal 53 YE 5276 CMP Sensor Signal Intake Bank 2 54 GY 2701 5-Volt Reference 55 D-GN 485 TP Sensor 1 Signal 56 L-GN/BK 5266 MAP Sensor Signal 57 GY 705 5-Volt Reference 58 L-BU 2123 Ignition Control 3 59 PU/WH 5024 Low Reference 60-61 - - Not Used 62 L-GN/BK 1745 Fuel Injector 2 Control 63 TN 1744 Fuel Injector 1 Control 64 YE/BK 846 Fuel Injector 6 Control
Engine Control Module (ECM) C2 Connector Part Information OEM: 1 928 403 514 (Bosch) 12186705 (Delphi) Service: See Catalog 64-Way F (BK) Pin Wire Color Circuit No. Function 1 PK 39 Ignition 1 Voltage 2 BK/WH 3122 HO2S Heater Low Control Sensor 2 3 PK 439 Ignition 1 Voltage 4 D-BU 473 High Speed Cooling Fan Relay Control 5 WH 121 Engine Speed Signal 6 - - Not Used 7 WH/BK 1164 5-Volt Reference 8 PU 1272 Low Reference 9 RD/BK 380 A/C Refrigerant Pressure Sensor Signal 10 WH 17 Stop Lamp Switch Signal 11 TN 472 IAT Sensor Signal 12 D-GN 890 Fuel Tank Pressure Sensor Signal 13-14 - - Not Used 15 OG/BK 463 Requested Torque Signal 16 - - Not Used 17 PK 39 Ignition 1 Voltage 18 - - Not Used 19 D-GN/WH 465 Fuel Pump Relay Control 20 D-GN 335 Low Speed Cooling Fan Relay Control 21 - - Not Used 22 D-GN 389 Vehicle Speed Signal 23 D-BU 6105 High Speed GMLAN Serial Data Bus + 24 BN 5069 Main Relay Control 25 BK 2759 Low Reference 26 BK 2760 Low Reference 27-28 - - Not Used 29 PU 3120 HO2S High Signal 30-31 - - Not Used 32 OG/BK 1786 Park/Neutral Signal 33 WH 1310 EVAP Canister Vent Solenoid Control 34 - - Not Used 35 YE/BK 625 Starter Enable Relay Control 36 OG 540 Battery Positive Voltage 37 TN/BK 464 Delivered Torque Signal 38 - - Not Used 39 GY 2709 5-Volt Reference 40 BN 1271 Low Reference 41 - - Not Used 42 PU 1589 Fuel Level Sensor Signal 43 YE 492 MAF Sensor Signal 44 L-BU 1162 APP Sensor 2 Signal 45-47 - - Not Used 48 D-GN 1049 ECM Class 2 Serial Data 49 D-GN/WH 459 A/C Compressor Clutch Relay Control 50 BN/WH 419 MIL Control 51-54 - - Not Used 55 L-BU 6106 High Speed GMLAN Serial Data Bus - 56 TN 1274 5-Volt Reference 57 TN/WH 3121 HO2S Low Signal 58 BN 1141 Ignition 3 Voltage 59 GY 1884 Cruise Control Set/Coast and Resume/Accelerate Switch Signal 60 D-BU 1161 APP Sensor 1 Signal 61-64 - - Not Used
Engine Controls Connector End Views
Accelerator Pedal Position (APP) Sensor Connector Part Information OEM: 15326829 Service: 88953153 6-Way F GT 150 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) Actuator Solenoid Exhaust Bank 1 Connector Part Information OEM: 7283-7526-30 (Yazaki) Service: See Catalog 2-Way F (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5293 Ignition 1 Voltage 2 L-GN 5282 CMP Actuator Solenoid Control Exhaust Bank 1
Camshaft Position (CMP) Actuator Solenoid Intake Bank 1 Connector Part Information OEM: 7283-7526-30 (Yazaki) Service: See Catalog 2-Way F (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5293 Ignition 1 Voltage 2 PU 5284 CMP Actuator Solenoid Control Intake Bank 1
Camshaft Position (CMP) Actuator Solenoid Exhaust Bank 2 Connector Part Information OEM: 7283-7526-30 (Yazaki) Service: See Catalog 2-Way F (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5293 Ignition 1 Voltage 2 WH/BK 5283 CMP Actuator Solenoid Control Exhaust Bank 2
Camshaft Position (CMP) Actuator Solenoid Intake Bank 2 Connector Part Information OEM: 7283-7526-30 (Yazaki) Service: See Catalog 2-Way F (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5293 Ignition 1 Voltage 2 OG/BK 5272 CMP Actuator Solenoid Control Intake Bank 2
Camshaft Position (CMP) Sensor Bank 1 Exhaust Connector Part Information OEM: 1928403966 (Bosch) Service: See Catalog 3-Way F (BK) Pin Wire Color Circuit No. Function 1 TN 470 Low Reference 2 D-GN 5273 CMP Sensor Signal Exhaust Bank 1 3 GY 705 5-Volt Reference
Camshaft Position (CMP) Sensor Bank 1 Intake Connector Part Information OEM: 1928403966 (Bosch) Service: See Catalog 3-Way F (BK) Pin Wire Color Circuit No. Function 1 TN 470 Low Reference 2 OG 5275 CMP Sensor Signal Intake Bank 1 3 GY 705 5-Volt Reference
Camshaft Position (CMP) Sensor Bank 2 Exhaust Connector Part Information OEM: 1928403966 (Bosch) Service: See Catalog 3-Way F (BK) Pin Wire Color Circuit No. Function 1 TN 470 Low Reference 2 PU 5274 CMP Sensor Signal Exhaust Bank 2 3 GY 705 5-Volt Reference
Camshaft Position (CMP) Sensor Bank 2 Intake Connector Part Information OEM: 1928403966 (Bosch) Service: See Catalog 3-Way F (BK) Pin Wire Color Circuit No. Function 1 TN 470 Low Reference 2 YE 5276 CMP Sensor Signal Intake Bank 2 3 GY 705 5-Volt Reference
Crankshaft Position (CKP) Sensor Connector Part Information OEM: 1928403874 (Bosch) Service: See Catalog 2-Way F (BK) Pin Wire Color Circuit No. Function 1 PU/WH 5024 Low Reference 2 WH/BK 5039 CKP Sensor Signal
Engine Coolant Temperature (ECT) Sensor Connector Part Information OEM: 1928403874 (Bosch) Service: See Catalog 2-Way F (BK) Pin Wire Color Circuit No. Function 1 YE 410 ECT Sensor Signal 2 TN 470 Low Reference
Evaporative Emission (EVAP) Canister Purge Solenoid Valve Connector Part Information OEM: 1928404072 (Bosch) Service: See Catalog 2-Way F (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5293 Ignition 1 Voltage 2 D-GN/WH 428 EVAP Canister Purge Solenoid Valve Control
Evaporative Emission (EVAP) Canister Vent Solenoid Valve Connector Part Information OEM: 12052643 Service: 12101858 2-Way F Metri-Pack 150 Series Sealed (RD) Pin Wire Color Circuit No. Function A OG 2840 Battery Positive Voltage B WH 1310 EVAP Canister Vent Solenoid Control
Fuel Injector 1 Connector Part Information OEM: 15305086 Service: 15306318 2-Way F Metri-Pack Tangless 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A WH 5291 Ignition 1 Voltage B TN 1744 Fuel Injector 1 Control
Fuel Injector 2 Connector Part Information OEM: 15305086 Service: 15306318 2-Way F Metri-Pack Tangless 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A WH 5292 Ignition 1 Voltage B L-GN/BK 1745 Fuel Injector 2 Control
Fuel Injector 3 Connector Part Information OEM: 15305086 Service: 15306318 2-Way F Metri-Pack Tangless 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A WH 5291 Ignition 1 Voltage B PK/BK 1746 Fuel Injector 3 Control
Fuel Injector 4 Connector Part Information OEM: 15305086 Service: 15306318 2-Way F Metri-Pack Tangless 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A WH 5292 Ignition 1 Voltage B L-BU/BK 844 Fuel Injector 4 Control
Fuel Injector 5 Connector Part Information OEM: 15305086 Service: 15306318 2-Way F Metri-Pack Tangless 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A WH 5291 Ignition 1 Voltage B TN/WH 845 Fuel Injector 5 Control
Fuel Injector 6 Connector Part Information OEM: 15305086 Service: 15306318 2-Way F Metri-Pack Tangless 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A WH 5292 Ignition 1 Voltage B YE/BK 846 Fuel Injector 6 Control
Fuel Pump and Sender Assembly Connector Part Information OEM: 15326631 Service: 15306360 4-Way F GT 280 Series Sealed (BK) Pin Wire Color Circuit No. Function A BK 1850 Ground B PU 30 Fuel Level Sensor Signal C BK/WH 651 Signal Ground D GY 120 Fuel Pump Supply Voltage
Fuel Tank Pressure Sensor Connector Part Information OEM: 12059595 Service: 88986451 3-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A OG/BK 469 Low Reference B D-GN 890 Fuel Tank Pressure Sensor Signal C GY 416 5-Volt Reference
Heated Oxygen Sensor (HO2S) 1 Connector Part Information OEM: 42122200 (FEP) Service: See Catalog 6-Way F Flat Contact Housing Sealed (BK) Pin Wire Color Circuit No. Function 1 PU/WH 1665 HO2S High Signal 2 WH 5279 HO2S Pump Current 3 PK/BK 5293 Ignition 1 Voltage 4 GY/WH 3113 HO2S Heater Low Control Sensor 1 5 TN 1664 HO2S Low Signal 6 L-GN 5278 HO2S Input Pump Current Sensor 1
Heated Oxygen Sensor (HO2S) 2 Connector Part Information OEM: 12092839 Service: 12092839 5-Way M Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A TN/WH 3121 HO2S Low Signal B PU 3120 HO2S High Signal C - - Not Available D BK/WH 3122 HO2S Heater Low Control Sensor 2 E PK 339 Ignition 1 Voltage
Ignition Coil 1 Connector Part Information OEM: 1928403441 (Bosch) Service: See Catalog 4-Way F (BK) Pin Wire Color Circuit No. Function 1 PU 2121 Ignition Control 1 2 PK/BK 5291 Ignition 1 Voltage 3 BK/WH 1551 Ground 4 BK 1550 Ground
Ignition Coil 2 Connector Part Information OEM: 1928403441 (Bosch) Service: See Catalog 4-Way F (BK) Pin Wire Color Circuit No. Function 1 OG/WH 2122 Ignition Control 2 2 PK/BK 5292 Ignition 1 Voltage 3 BK/WH 151 Ground 4 BK 150 Ground
Ignition Coil 3 Connector Part Information OEM: 1928403441 (Bosch) Service: See Catalog 4-Way F (BK) Pin Wire Color Circuit No. Function 1 L-BU 2123 Ignition Control 3 2 PK/BK 5291 Ignition 1 Voltage 3 BK/WH 1551 Ground 4 BK 1550 Ground
Ignition Coil 4 Connector Part Information OEM: 1928403441 (Bosch) Service: See Catalog 4-Way F (BK) Pin Wire Color Circuit No. Function 1 D-GN/WH 2124 Ignition Control 4 2 PK/BK 5292 Ignition 1 Voltage 3 BK/WH 151 Ground 4 BK 150 Ground
Ignition Coil 5 Connector Part Information OEM: 1928403441 (Bosch) Service: See Catalog 4-Way F (BK) Pin Wire Color Circuit No. Function 1 D-GN 2125 Ignition Control 5 2 PK/BK 5291 Ignition 1 Voltage 3 BK/WH 1551 Ground 4 BK 1550 Ground
Ignition Coil 6 Connector Part Information OEM: 1928403441 (Bosch) Service: See Catalog 4-Way F (BK) Pin Wire Color Circuit No. Function 1 L-BU/WH 2126 Ignition Control 6 2 PK/BK 5292 Ignition 1 Voltage 3 BK/WH 151 Ground 4 BK 150 Ground
Knock Sensor (KS) 1 Connector Part Information OEM: 1928403874 (Bosch) Service: See Catalog 2-Way F (BK) Pin Wire Color Circuit No. Function 1 D-BU 496 KS Signal Bank 1 2 GY 1716 KS Low Reference Bank 1
Knock Sensor (KS) 2 Connector Part Information OEM: 1928403874 (Bosch) Service: See Catalog 2-Way F (BK) Pin Wire Color Circuit No. Function 1 L-BU 1876 KS Signal Bank 2 2 TN 407 KS Low Reference Bank 2
Manifold Absolute Pressure (MAP) Sensor Connector Part Information OEM: 1928403966 (Bosch) Service: See Catalog 3-Way F (BK) Pin Wire Color Circuit No. Function 1 GY 605 5-Volt Reference 2 TN 470 Low Reference 3 OG/BK 5266 MAP Sensor Signal
Mass Airflow (MAF)/Intake Air Temperature (IAT) Sensor Connector Part Information OEM: 15327729 (Delphi) 1928403200 (Bosch) Service: See Catalog 5-Way F Jr-Power Timer Sealed (BK) Pin Wire Color Circuit No. Function 1 TN 472 IAT Sensor Signal 2 PK 339 Ignition 1 Voltage 3 BK 2760 Low Reference 4 GY 2709 5-Volt Reference 5 YE 492 MAF Sensor Signal
Throttle Actuator Control (TAC) Module Connector Part Information OEM: 19676161 (Bosch) Service: See Catalog 6-Way F (BK) Pin Wire Color Circuit No. Function 1 D-GN 485 TP Sensor 1 Signal 2 GY 2701 5-Volt Reference 3 BN 582 TAC Motor Control 2 4 PU 486 TP Sensor 2 Signal 5 YE 581 TAC Motor Control 1 6 TN 2752 Low Reference
DIAGNOSTIC CODE INDEX
| DTC | Description |
|---|---|
| DTC P0008 | Engine Position System Performance Bank 1 |
| DTC P0009 | Engine Position System Performance Bank 2 |
| DTC P0010, P0013, P0020 or P0023 | Intake/Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit |
| DTC P0011, P0014, P0021 or P0024 | Intake/Exhaust Camshaft Position (CMP) System Performance |
| DTC P0016, P0017, P0018 or P0019 | Crankshaft Position (CKP) - Intake/Exhaust Camshaft Position (CMP) Correlation |
| DTC P0030 or P0036 | HO2S Heater Control Circuit Sensor |
| DTC P0031 or P0037 | HO2S Heater Control Circuit Low Voltage Sensor |
| DTC P0032 or P0038 | HO2S Heater Control Circuit High Voltage Sensor |
| DTC P0053 | HO2S Internal Heater Resistance Bank 1 Sensor 1 |
| DTC P0101 | Mass Air Flow (MAF) Sensor Performance |
| DTC P0102 | Mass Air Flow (MAF) Sensor Circuit Low Voltage |
| DTC P0103 | Mass Air Flow (MAF) Sensor Circuit High Voltage |
| DTC P0112 | Intake Air Temperature (IAT) Sensor Circuit Low Voltage |
| DTC P0113 | Intake Air Temperature (IAT) Sensor Circuit High Voltage |
| DTC P0117 | Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage |
| DTC P0118 | Engine Coolant Temperature (ECT) Sensor Circuit High Voltage |
| DTC P0121 | Throttle Position (TP) Sensor 1 Performance |
| DTC P0122 | Throttle Position (TP) Sensor 1 Circuit Low Voltage |
| DTC P0123 | Throttle Position (TP) Sensor 1 Circuit High Voltage |
| DTC P0125 | Engine Coolant Temperature (ECT) Insufficient for Closed Loop Fuel Control |
| DTC P0128 | Engine Coolant Temperature (ECT) Below Thermostat Regulating Temperature |
| DTC P0130 | HO2S Circuit Sensor 1 |
| DTC P0131 | HO2S Circuit Low Voltage Sensor 1 |
| DTC P0132 | HO2S Circuit High Voltage Sensor 1 |
| DTC P0133 | HO2S Slow Response Sensor 1 |
| DTC P0135 | HO2S Heater Performance Sensor 1 |
| DTC P0137 | HO2S Circuit Low Voltage Sensor 2 |
| DTC P0138 | HO2S Circuit High Voltage Sensor 2 |
| DTC P0140 | HO2S Circuit Insufficient Activity Sensor 2 |
| DTC P0141 | HO2S Heater Performance Sensor 2 |
| DTC P0201-P0206 | Injector Control Circuit |
| DTC P0221 | Throttle Position (TP) Sensor 2 Performance |
| DTC P0222 | Throttle Position (TP) Sensor 2 Circuit Low Voltage |
| DTC P0223 | Throttle Position (TP) Sensor 2 Circuit High Voltage |
| DTC P0261, P0264, P0267, P0270, P0273 or P0276 | Injector Control Circuit Low Voltage |
| DTC P0262, P0265, P0268, P0271, P0274 or P0277 | Injector Control Circuit High Voltage |
| DTC P0300 | Engine Misfire Detected |
| DTC P0301-P0306 | Cylinder Misfire Detected |
| DTC P0318 | Rough Road Sensor Circuit |
| DTC P0324 | Knock Sensor (KS) Module Performance |
| DTC P0327 or P0332 | Knock Sensor (KS) Circuit Low Voltage |
| DTC P0328 or P0333 | Knock Sensor (KS) Circuit High Voltage |
| DTC P0335 | Crankshaft Position (CKP) Sensor Circuit |
| DTC P0336 | Crankshaft Position (CKP) Sensor Performance |
| DTC P0338 | Crankshaft Position (CKP) Sensor Circuit High Duty Cycle |
| DTC P0341, P0346, P0366 or P0391 | Intake/Exhaust Camshaft Position (CMP) Sensor Performance |
| DTC P0342, P0347, P0367 or P0392 | Intake/Exhaust Camshaft Position (CMP) Sensor Circuit Low Voltage |
| DTC P0343, P0348, P0368 or P0393 | Intake/Exhaust Camshaft Position (CMP) Sensor Circuit High Voltage |
| DTC P0351-P0356 | Ignition Coil Control Circuit |
| DTC P0420 | Catalyst System Low Efficiency |
| DTC P0442 | Evaporative Emission (EVAP) System Small Leak Detected |
| DTC P0443 | Evaporative Emission (EVAP) Purge Solenoid Control Circuit |
| DTC P0446 | Evaporative Emission (EVAP) Vent System Performance |
| DTC P0449 | Evaporative Emission (EVAP) Vent Solenoid Control Circuit |
| DTC P0451 | Fuel Tank Pressure (FTP) Sensor Performance |
| DTC P0452 | Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage |
| DTC P0453 | Fuel Tank Pressure (FTP) Sensor Circuit High Voltage |
| DTC P0455 | Evaporative Emission (EVAP) System Large Leak Detected |
| DTC P0458 | Evaporative Emission (EVAP) Purge Solenoid Control Circuit Low Voltage |
| DTC P0459 | Evaporative Emission (EVAP) Purge Solenoid Control Circuit High Voltage |
| DTC P0496 | Evaporative Emission (EVAP) System Flow During Non-Purge |
| DTC P0498 | Evaporative Emission (EVAP) Vent Solenoid Control Circuit Low Voltage |
| DTC P0499 | Evaporative Emission (EVAP) Vent Solenoid Control Circuit High Voltage |
| DTC P0506 or P0507 | Idle Speed |
| DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683 or P2610 | Control Module |
| DTC P0627 | Fuel Pump Relay Control Circuit |
| DTC P0628 | Fuel Pump Relay Control Circuit Low Voltage |
| DTC P0629 | Fuel Pump Relay Control Circuit High Voltage |
| DTC P0638 | Throttle Actuator Control (TAC) Command Performance |
| DTC P0650 | Malfunction Indicator Lamp (MIL) Control Circuit |
| DTC P0685, P0686, P0687, P0689 or P0690 | Engine Controls Ignition Relay |
| DTC P0700 | Transmission Control Module (TCM) Requested MIL Illumination |
| DTC P0864 | TCM Communication Circuit Performance |
| DTC P1011-P1014 | Intake/Exhaust Camshaft Position (CMP) Actuator Park Position |
| DTC P1551 | Throttle Valve Rest Position Not Reached During Learn |
| DTC P167A | Control Module HO2S Bank 1 Sensor 1 System Performance |
| DTC P2088, P2090, P2092 or P2094 | Intake/Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit Low Voltage |
| DTC P2089, P2091, P2093 or P2095 | Intake/Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit High Voltage |
| DTC P2096 | Post Catalyst Fuel Trim System Low Limit |
| DTC P2097 | Post Catalyst Fuel Trim System High Limit |
| DTC P2100 | Throttle Actuator Control (TAC) Motor Control Circuit |
| DTC P2101 | Control Module Throttle Actuator Position Performance |
| DTC P2105 | Throttle Actuator Control (TAC) System - Forced Engine Shut down |
| DTC P2107 | Throttle Actuator Control (TAC) Module Internal Circuit |
| DTC P2119 | Throttle Closed Position Performance |
| DTC P2122 | Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage |
| DTC P2123 | Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage |
| DTC P2127 | Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage |
| DTC P2128 | Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage |
| DTC P2138 | Accelerator Pedal Position (APP) Sensor 1-2 Correlation |
| DTC P2176 | Minimum Throttle Position Not Learned |
| DTC P2177 | Fuel Trim System Lean at Cruise or Accel |
| DTC P2178 | Fuel Trim System Rich at Cruise or Accel |
| DTC P2187 | Fuel Trim System Lean at Idle |
| DTC P2188 | Fuel Trim System Rich at Idle |
| DTC P2195 | HO2S Signal Biased Lean Sensor 1 |
| DTC P2196 | HO2S Signal Biased Rich Sensor 1 |
| DTC P2227 | Barometric Pressure (BARO) Sensor Performance |
| DTC P2228 | Barometric Pressure (BARO) Sensor Circuit Low Voltage |
| DTC P2229 | Barometric Pressure (BARO) Sensor Circuit High Voltage |
| DTC P2231 | HO2S Signal Circuit Shorted to Heater Circuit Sensor 1 |
| DTC P2232 | HO2S Signal Circuit Shorted to Heater Circuit Sensor 2 |
| DTC P2237 | HO2S Pumping Current Control Circuit Sensor 1 |
| DTC P2243 | HO2S Reference Voltage Circuit Sensor 1 |
| DTC P2251 | HO2S Reference Ground Circuit Sensor 1 |
| DTC P2270 | HO2S Signal Stuck Lean Sensor 2 |
| DTC P2271 | HO2S Signal Stuck Rich Sensor 2 |
| DTC P2297 | HO2S Performance During Decel Fuel Cut-Off (DFCO) Sensor 1 |
| DTC P2300, P2303, P2306, P2309, P2312 or P2315 | Ignition Coil Control Circuit Low Voltage |
| DTC P2301, P2304, P2307, P2310, P2313 or P2316 | Ignition Coil Control Circuit High Voltage |
| DTC P2626 | HO2S Pumping Current Trim Circuit Sensor 1 |
DIAGNOSTIC CODE INDEX
Removal Procedure
Note. Always turn the ignition off when installing or removing the ECM connectors in order to prevent damage to the components.
- Using a scan tool, retrieve the percentage of remaining engine oil. Record the remaining engine oil life.
- Turn the ignition OFF.
- Use a DVOM in order to measure the main relay circuit voltage at the engine control module (ECM) fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/lacrosse/i-2004-2009/remont/electrical-component-locations/#wiring-systems-component-views) in Wiring Systems.
- Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
- Remove the ECM fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/lacrosse/i-2004-2009/remont/electrical-component-locations/#wiring-systems-component-views) in Wiring Systems.
- Remove the TCM/IPC fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/lacrosse/i-2004-2009/remont/electrical-component-locations/#wiring-systems-component-views) in Wiring Systems.
- Remove the ECM/TCM fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/lacrosse/i-2004-2009/remont/electrical-component-locations/#wiring-systems-component-views) in Wiring Systems.
- Unlock the body side (outboard) ECM electrical connector. Depress the ECM electrical connector lever lock (1). Simultaneously rotate the ECM connector clamp lever and depress the lock slide (2).
- Remove the body side (outboard) ECM connector.
- Unlock and remove the engine side (inboard) ECM connector.
- Remove the ECM redundant ground wire and bolt from the ECM.
- Remove the ECM bolts.
- Remove the ECM.
- If necessary, perform the following steps: Remove the ECM bracket bolts. Remove the ECM bracket (1).
Installation Procedure
- Install the ECM bracket, as necessary.
- Install the ECM bracket bolts. Tighten: Tighten the ECM bracket bolts to 10 N.m (89 lb in).
- Install the ECM.
- Install the ECM bolts. Tighten: Tighten the ECM bolts to 10 N.m (89 lb in).
- Install the ECM redundant ground and bolt to the ECM. Tighten: Tighten the ECM redundant ground wire bolt to 5 N.m (44 lb in).
- Install the engine side (inboard) ECM connector.
- Install the body side (outboard) ECM connector.
- Install the ECM/TCM fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/lacrosse/i-2004-2009/remont/electrical-component-locations/#wiring-systems-component-views) in Wiring Systems.
- Install the TCM/IPC fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/lacrosse/i-2004-2009/remont/electrical-component-locations/#wiring-systems-component-views) in Wiring Systems.
- Install the ECM fuse in the underhood fuse block. Refer to «Electrical Center Identification Views»(/buick/lacrosse/i-2004-2009/remont/electrical-component-locations/#wiring-systems-component-views) in Wiring Systems.
- Connect the battery negative cable to the battery. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
- Program the ECM. Refer to «Control Module References»(/buick/lacrosse/i-2004-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) in Computer/Integrating Systems.
- Turn OFF the ignition for at least 5 seconds after the programming event is complete.
Description
The engine control module (ECM) learns the idle position of the throttle body to ensure the correct idle operation. Anytime the ECM or the throttle body is replaced, the ECM must learn the idle position. The engine idle may be unstable or a DTC may set if the idle position is not learned.
Conditions for Running the Idle Learn Procedure
- DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0638, P2100, P2101, P2105, P2107 and P2119 are not set.
- The engine speed is less than 40 RPM.
- The vehicle speed is 0 km/h (0 mph).
- The accelerator pedal position is less than 14.9 percent.
- The ignition 1 voltage is more than 10 volts.
- The engine coolant temperature is between 5-85°C (41-185°F).
- The intake air temperature is between 5-60°C (41-140°F).
Idle Learn Procedure
- Turn OFF the ignition for 30 seconds.
- Turn ON the ignition, with the engine OFF for 60 seconds.
- Turn OFF the ignition.
- Turn ON the ignition, with the engine OFF.
- Clear the DTCs with a scan tool.
| CAUTION | Allow sufficient time for the engine to cool before removing the ECT sensor. A hot engine may cause an excessive coolant loss or a personal injury. |
- Turn the ignition OFF.
- Partially drain the cooling system. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
- Remove the coolant temperature sensor electrical connector.
- Remove the coolant temperature sensor.
- Install the coolant temperature sensor. Tighten: Tighten the sensor to 22 N.m (16 lb ft).
- Install the coolant temperature sensor electrical connector.
- Inspect and fill the cooling system as necessary. Refer to «Draining and Filling Cooling System (L26 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) , «Draining and Filling Cooling System (LY7 Static Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) or «Draining and Filling Cooling System (L26, LY7, GE 47716 Fill)»(/buick/lacrosse/i-2004-2009/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
- Turn the ignition OFF.
- Remove the mass air flow (MAF) electrical connector.
- Remove the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Remove the MAF sensor fasteners.
- Remove the MAF sensor and the MAF sensor seal.
- Install the new MAF sensor seal and the MAF sensor.
- Install the MAF sensor screws. Tighten: Tighten the MAF sensor screws to 4 N.m (35 lb in).
- Install the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Install the MAF electrical connector.
- Turn the ignition OFF.
- Remove the sensor electrical connector.
- Remove the barometric pressure sensor bolt.
- Remove the barometric pressure sensor.
- Install the barometric pressure sensor.
- Install the barometric pressure sensor bolt. Tighten: Tighten the barometric pressure sensor bolt to 10 N.m (89 lb in).
- Install the sensor electrical connector.
Note. The Heated Oxygen Sensor (HO2S) and the Oxygen Sensor use a permanently attached pigtail and connector. Do not remove this pigtail from the Heated Oxygen Sensor. Damage or the removal of the pigtail or the connector could affect the proper operation of the sensor. Take care when handling the HO2S and the O2S. Keep the in-line electrical connector and the louvered end free of grease, dirt or other contaminants. Also avoid using cleaning solvents of any type. Do not drop the HO2S or the O2S. Do not roughly handle the HO2S or the O2S.
- Disconnect the oxygen sensor electrical connector.
- Remove the heated oxygen sensor (HO2S).
- Install the HO2S. Tighten: Tighten the HO2S 1 to 42 N.m (31 lb ft).
- Connect the oxygen sensor electrical connector.
Note. The Heated Oxygen Sensor (HO2S) and the Oxygen Sensor use a permanently attached pigtail and connector. Do not remove this pigtail from the Heated Oxygen Sensor. Damage or the removal of the pigtail or the connector could affect the proper operation of the sensor. Take care when handling the HO2S and the O2S. Keep the in-line electrical connector and the louvered end free of grease, dirt or other contaminants. Also avoid using cleaning solvents of any type. Do not drop the HO2S or the O2S. Do not roughly handle the HO2S or the O2S.
- Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
- Disconnect the heated oxygen sensor (HO2S) electrical connector.
- Remove the HO2S.
- Install the HO2S. Tighten: Tighten the HO2S 2 to 42 N.m (31 lb ft).
- Connect the HO2S electrical connector.
- Lower the vehicle.
- Turn the ignition OFF.
- Remove the closeout/insulator panel from under the dashboard on the drivers side. Refer to «Closeout/Insulator Panel Replacement - Left»(/buick/lacrosse/i-2004-2009/remont/gauges-instrument-panels/#instrument-panel-gages-and-console) in Instrument Panel, Gages and Console.
- Disconnect the accelerator pedal position (APP) sensor electrical connector from the accelerator pedal module.
- Remove the APP sensor mounting bolts.
- Remove the APP sensor from the vehicle.
- Position the APP sensor to the mounting plate.
- Install the APP sensor mounting bolts. Tighten: Tighten the APP sensor mounting bolts to 10 N.m (89 lb in).
- Connect the APP sensor electrical connector.
- 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.
- Install the closeout/insulator panel. Refer to «Closeout/Insulator Panel Replacement - Left»(/buick/lacrosse/i-2004-2009/remont/gauges-instrument-panels/#instrument-panel-gages-and-console) in Instrument Panel, Gages and Console.
- Turn the ignition OFF.
- Remove the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Remove the throttle body electrical connector.
- Unlock and reposition the wiring harness conduit.
- Remove the throttle body bolts.
- Remove the throttle body and gasket.
- Carefully clean the throttle body mounting surfaces of any gasket and/or seal material.
- Install the throttle body and NEW gasket.
- Install the throttle body bolts. Tighten: Tighten the throttle body bolts to 10 N.m (89 lb in).
- Install the wiring harness conduit.
- Install the throttle body electrical connector.
- Install the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
Service Procedure
- Remove the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Fully open the throttle valve in order to Inspect the throttle body bore and the throttle valve plate for any deposits.
- Use a clean shop towel and Top Engine Cleaner GM P/N 1052626 or equivalent product in order to clean the throttle body bore and the throttle valve plate. If necessary, use a parts cleaning brush in order to remove heavy deposits.
- Install the air cleaner duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
Pressure Relief Procedure
- Turn the ignition OFF.
- Remove the fuel pump fuse and the fuel pump relay. Refer to «Electrical Center Identification Views»(/buick/lacrosse/i-2004-2009/remont/electrical-component-locations/#wiring-systems-component-views) in Wiring Systems.
- Loosen the fuel filler cap to relieve the fuel tank vapor pressure.
- Attempt to start the engine and allow the engine to run until it stops.
- Remove the fuel pressure test port cap.
- Wrap a shop towel around the fuel pressure test port and use a small flat-bladed tool in order to depress (open) the fuel pressure test port valve.
- Place the shop towel in an approved container.
- Install the fuel pressure test port cap.
- Tighten the fuel filler cap.
- Relieve the fuel pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Remove the fuel pressure test port cap.
- Install the fuel pressure gage to the fuel pressure test port.
- Place the shop towel in an approved container.
- Perform any tests and/or diagnostics as needed.
- Relieve the fuel pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Remove the fuel pressure gage.
- Place the shop towel in an approved container.
- Install the fuel pressure test port cap.
Tools Required
- J 37088-A Fuel Line Disconnect Tool Set. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__special-tools) .
- J 44581 Fuel Line Disconnect Tool. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__special-tools) .
- Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Remove the retainer from the quick-connect fitting.
- Blow dirt out of the fitting using compressed air.
- Depending on the fuel line size and ability to access the fitting, choose the appropriate tool: J 37088-A or. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__special-tools) . J 44581 . See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__special-tools) . Insert the J 37088-A or. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__special-tools) . J 44581 into the female connector, then push inward to release the locking tabs. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__special-tools) .
- Pull the connection apart.
- Using a clean shop towel, wipe off the male pipe end.
- Inspect both ends of the fitting for dirt and burrs.
- Clean or replace the components as required.
- Apply a few drops of clean engine oil to the male pipe end.
- Push both sides of the quick-connect fitting together to cause the retaining tabs to snap into place.
- Pull on both sides of the quick-connect fitting to make sure the connection is secure.
- Install the retainer to the quick-connect fitting.
- 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.
- Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Blow dirt out of the fitting using compressed air.
- Squeeze the plastic tabs of the male end connector.
- Pull the connection apart.
- Using a clean shop towel, wipe off the male pipe end
- Inspect both ends of the fitting for dirt and burrs.
- Clean or replace the components as required.
- Apply a few drops of clean engine oil to the male pipe end.
- Push both sides of the quick-connect fitting together to cause the retaining tabs/fingers to snap into place.
- Pull on both sides of the quick-connect fitting to make sure the connection is secure.
- 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.
- J 42960-2 Fuel Flapper Door Holder. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__special-tools) .
- J 45004 Fuel Tank Drain Hose. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__special-tools) .
| CAUTION | Never drain or store fuel in an open container. Always use an approved fuel storage container in order to reduce the chance of fire or explosion. |
| CAUTION | Place a dry chemical (Class B) fire extinguisher nearby before performing any on-vehicle service procedures. Failure to follow these precautions may result in personal injury. |
Draining Procedure
- Remove the fuel filler cap.
- Install the J 42960-2 into the fuel fill pipe in order to hold the door open. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__special-tools) .
- Insert the J 45004 into the fuel tank until the hose reaches the bottom of the fuel tank. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__special-tools) .
- Use an air operated pump device in order to drain as much fuel through the fuel fill pipe as possible.
- Relieve the fuel system fuel pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2__fuel-pressure-relief-procedure) .
- Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2__fuel-tank-draining-procedure) .
- Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
- Loosen the fuel filler hose clamp (1) at the fuel tank (3).
- Remove the fuel tank filler hose from the fuel tank.
- Disconnect the fuel feed (4), the fuel return (2) and the evaporative emission (EVAP) (3) pipes at the fuel filter area. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Support the exhaust system.
- Remove the rubber exhaust pipe hangers in order to allow the exhaust system to drop slightly.
- Separate the two halves of the EVAP fresh air hose at the splice.
- Remove the fuel tank shield push pins (2).
- Remove the fuel tank shield (3).
- Support the fuel tank with a suitable jack.
- Remove the fuel tank strap bolts (2).
- Using the suitable jack lower the fuel tank.
- Disconnect the fuel sender assembly electrical connectors.
- Remove the fuel tank and place the tank in a suitable work area.
- Disconnect and remove the fuel feed (6), the fuel return (7) and the EVAP pipe (5) assemblies and the insulator clips from the fuel tank (1). Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Remove the EVAP canister (2) from the fuel tank (1).
- Remove the insulator pads from the fuel tank. Note the location of the insulator pads for installation.
- Install the insulator pads to the fuel tank.
- Install the EVAP canister (2) to the fuel tank (1).
- Install and connect the fuel feed (6), the fuel return (7) and the EVAP pipe (5) assemblies and the insulator clips to the fuel tank (1) as noted during removal. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Install the fuel tank to a suitable jack.
- Raise the fuel tank (1) to the original position.
- Install the fuel tank strap bolts (2). Tighten: Tighten the bolts to 48 N.m (35 lb ft).
- Remove the jack from the fuel tank.
- Position the fuel tank shield (3) to the fuel tank (1).
- Install the push pins (2).
- Install the two parts of the EVAP fresh air hose at the splice.
- Raise the exhaust system to the original position.
- Install the exhaust system to the exhaust pipe hangers.
- Connect the fuel feed (4), the fuel return (2) and the evaporative emission (EVAP) (3) pipes at the fuel filter area. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Install the fuel tank filler hose to the fuel tank.
- Fully seat the filler hose (4) on the fuel tank port (2).
- Ensure that the clamp (1) is properly located on the tank port between the bead (5) and the tank (3). Tighten: Tighten the hose clamp to 2.5 N.m (22 lb in).
- Lower the vehicle.
- Add fuel and install the fuel fill cap.
- Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
- Inspect the fuel system for leaks by performing the following steps: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
- Install fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-38l) in Engine Mechanical - 3.8L.
- Remove the fuel sender assembly. Refer to «Fuel Sender Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Remove the fuel tank pressure sensor (7) from the fuel sender assembly.
- Install the new fuel tank pressure sensor (7) to the fuel sender assembly.
- Install the fuel sender assembly. Refer to «Fuel Sender Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
J 45722 Fuel Sender Lock Ring Wrench. See Special Tools .
- Remove the fuel tank. Refer to «Fuel Tank Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Disconnect the fuel sender module electrical connectors.
- Disconnect the fuel pipes from the fuel sender. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Use the J 45722 and a long breaker-bar in order to unlock the fuel sender lock ring. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__special-tools) . Turn the fuel sender lock ring in a counterclockwise direction.
- Remove the fuel sender lock ring (1) and the fuel sender (2) from the fuel tank.
- Remove and discard the fuel sender seal (3).
- Remove the fuel level sensor from the fuel sender module. Refer to «Fuel Tank Pressure Sensor Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Place the lock ring on a flat surface. Measure the clearance between to lock ring and the flat surface using a feeler gage at 7 points.
- If the warpage is less than 0.41 mm (0.016 in), the lock ring does not require replacement.
- If the warpage is greater than 0.41 mm (0.016 in), the lock ring must be replaced.
- Install the fuel level sensor to the fuel sender module. Refer to «Fuel Tank Pressure Sensor Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Clean the fuel sender sealing flange.
- Install the NEW fuel sender seal (3) to the fuel tank seal groove.
- Install the fuel sender (2) and the fuel sender lock ring (1).
- Use the J 45722 in order to install the fuel sender lock ring. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__special-tools) . Turn the fuel sender lock ring in a clockwise direction.
- Install the fuel pipes to the fuel sender. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Install the fuel sender sensor electrical connectors.
- Install the fuel tank. Refer to «Fuel Tank Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Remove the fuel sender from the fuel tank. Refer to «Fuel Tank Module Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Disconnect the fuel level sensor electrical connector located in the module cover.
- Use a small flat-bladed tool in order to disengage the fuel level sensor retainer.
- Slide the fuel level sensor down in order to remove the fuel level sensor from the fuel sender module.
- Slide the fuel level sensor up in order to install the fuel level sensor to the fuel sender module.
- Ensure that the fuel level sensor retainer is properly engaged.
- Connect the fuel level sensor electrical connector.
- Install the fuel sender to the fuel tank. Refer to «Fuel Tank Module Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2__fuel-pressure-relief-procedure) .
- Clean all engine fuel pipe connections.
- Clean areas surrounding the engine fuel pipe connections.
- Disconnect the fuel feed and evaporative emission (EVAP) pipes from the engine. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) and «Quick Connect Fitting(s) Service (Metal Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
- Disconnect the fuel feed and EVAP pipes from the fuel tank. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Cap the fuel pipes in order to stop any fuel leakage.
- Remove the fuel pipe retainers with the fuel pipes.
- Note the position of the fuel and EVAP pipes and the fuel and EVAP pipe attaching hardware for installation.
- Inspect the pipes for bends, kinks and cracks.
- Replace the pipe or pipes as required.
- Install the fuel pipe attaching hardware as noted during removal.
- Remove the caps from the fuel pipes.
- Connect the fuel feed and EVAP pipes to the fuel tank. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Lower the vehicle.
- Connect the fuel feed and EVAP pipes to the engine. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) and «Quick Connect Fitting(s) Service (Metal Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Lower the vehicle.
- Tighten the fuel fill cap.
- Reconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
- Inspect for fuel leaks with the following procedure: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
Cleaning Procedure
- Relieve the fuel system fuel pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2__fuel-pressure-relief-procedure) .
- Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2__fuel-tank-draining-procedure) .
- Remove the fuel tank. Refer to «Fuel Tank Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Remove the fuel sender assembly. Refer to «Fuel Sender Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Inspect the fuel pump inlet for dirt and debris. If dirt and debris are found, the fuel pump needs to be replaced.
- Flush the fuel tank with hot water.
- Pour the water out of the fuel sender assembly opening in the fuel tank. Rock the fuel tank in order to be sure that the removal of the water from the fuel tank is complete.
- Allow the tank to dry completely before reassembly.
- Install the fuel sender assembly. Refer to «Fuel Sender Assembly Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Install the fuel tank. Refer to «Fuel Tank Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Add fuel and install the fuel tank filler pipe cap.
- Inspect for fuel leaks using the following procedure: Turn ON the ignition for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition. Inspect for fuel leaks.
| CAUTION | Refer to Gasoline/Gasoline Vapors Caution in Cautions and Notices. |
- Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Remove the upper intake manifold. Refer to «Intake Manifold Replacement - Upper»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) in Engine Mechanical - 3.6L.
- Remove the fuel pipe retaining clip.
- Disconnect the fuel feed pipe (2) from the fuel injector rail. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Use compressed air in order to remove debris from the area where the fuel injectors enter the intake manifold.
- Remove the fuel rail bolts.
- Remove the fuel rail with the fuel injectors.
- Disengage the fuel injector electrical connector lock.
- Disconnect the fuel injector electrical connector.
- Remove the fuel injector retainer clip.
- Remove the fuel injector.
- Remove and discard the fuel injector seals.
- Install NEW fuel injector seals.
- Install the fuel injector.
- Install the fuel injector retainer clip.
- Install the fuel injector electrical connector.
- Engage the fuel injector electrical connector lock.
- Install the fuel rail with the fuel injectors.
- Install the fuel rail bolts. Tighten: Tighten the fuel rail bolts to 10 N.m (89 lb in).
- Connect the fuel feed pipe (2) to the fuel rail. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Install the fuel pipe retaining clip.
- Install the upper intake manifold. Refer to «Intake Manifold Replacement - Upper»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) in Engine Mechanical - 3.6L.
- Turn the ignition OFF.
- Disconnect the purge line from the purge valve solenoid.
- Disconnect the purge valve solenoid electrical connector.
- Disconnect the purge line from the manifold side of the purge valve solenoid.
- Remove the purge valve solenoid and bolt from the intake manifold.
- Install the purge valve solenoid to the intake manifold. Tighten: Tighten the purge solenoid bolt to 10 N.m (89 lb in).
- Connect the purge line to the manifold side of the purge valve solenoid.
- Disconnect the purge valve solenoid electrical connector.
- Connect the purge line to the purge valve solenoid.
- Remove the fuel tank. Refer to «Fuel Tank Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Disconnect the evaporative emission (EVAP) canister vent solenoid harness connector.
- Remove the EVAP vent hose from EVAP canister solenoid.
- Depress the EVAP canister vent bracket tab to release the EVAP canister vent solenoid.
- Remove the EVAP canister solenoid from the fuel tank.
- Slide the EVAP canister vent solenoid on the EVAP canister vent bracket until the solenoid snaps into place.
- Connect the EVAP vent hose to the EVAP canister vent solenoid.
- Connect the EVAP canister vent solenoid harness connector.
- Install the fuel tank. Refer to «Fuel Tank Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
- Disconnect the evaporative emission (EVAP) purge pipe connector at the fuel filter area. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Disconnect the EVAP purge pipe (8) from the EVAP canister (1). Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Remove the EVAP purge pipe (8).
- Connect the EVAP purge pipe (8) to the EVAP canister. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Connect the EVAP purge pipe at the fuel filter area. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Lower the vehicle.
- Remove the fuel tank. Refer to «Fuel Tank Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Disconnect the EVAP vent hose (6), the EVAP purge pipe (8) and the EVAP vapor pipe (7) from the EVAP canister (1). Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Release the EVAP canister retaining strap.
- Remove the EVAP canister (1) from the fuel tank.
- Position the EVAP canister (1) on the fuel tank.
- Install the new EVAP canister retaining strap.
- Connect the EVAP vent hose (6), the EVAP purge pipe (8) and the EVAP vapor pipe (7) to the EVAP canister (1). Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
- Install the fuel tank. Refer to «Fuel Tank Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-38l-introduction-2-of-2) .
Scheme 27
- Turn the ignition OFF.
- Remove the engine cover. Refer to «Fuel Injector Sight Shield Replacement»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) .
- If you are replacing the ignition coil for cylinder 5, remove and reposition the intake manifold. Perform the following steps. Disconnect the air cleaner duct from the throttle body. Disconnect the positive crankcase ventilation (PCV) hose from the right bank camshaft cover. IMPORTANT: Do NOT separate the upper intake manifold from the lower intake manifold. Remove the intake manifold bolts. Remove the intake manifold brace bolts (1 and 2) and the brace. Remove the upper intake manifold. Refer to «Intake Manifold Replacement - Upper»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) .
- Remove the ignition coil electrical connectors.
- Remove the ignition coil bolts.
- Remove the ignition coils.
- Install the ignition coils.
- Install the ignition coil bolts. Tighten: Tighten the ignition coil bolts to 10 N.m (89 lb in).
- Install the ignition coil electrical connectors.
- If necessary, install the intake manifold. Refer to «Intake Manifold Replacement - Upper»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) .
- Install the engine cover. Refer to «Fuel Injector Sight Shield Replacement»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) .
- Turn the ignition OFF.
- Remove the engine cover to have it checked. Refer to «Fuel Injector Sight Shield Replacement»(/buick/lacrosse/i-2004-2009/remont/mechanical/#engine-mechanical-36l-ly7-repair-instructions-1-of-5) .
- If you are replacing the ignition coil for cylinder 2, remove and reposition the intake manifold. Perform the following steps. Disconnect the air cleaner duct from the throttle body. Disconnect the positive crankcase ventilation (PCV) hose from the right bank camshaft cover. IMPORTANT: Do NOT separate the upper intake manifold from the lower intake manifold. Remove the intake manifold bolts. Remove the intake manifold brace bolts (1 and 2) and the brace. Remove and reposition the upper intake manifold with the lower intake manifold in order to gain sufficient clearance for ignition coil removal.
- Remove the ignition coil electrical connectors.
- Remove the ignition coil bolts.
- Remove the ignition coils.
- Install the ignition coils.
- Install the ignition coil bolts. Tighten: Tighten the ignition coil bolts to 10 N.m (89 lb in).
- Install the ignition coil electrical connectors.
Spark Plug Usage
- Ensure that the correct spark plug is installed. An incorrect spark plug causes driveability conditions. Refer to «Ignition System Specifications»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__ignition-system-specifications) for the correct spark plug.
- Ensure that the spark plug has the correct heat range. An incorrect heat range causes the following conditions: Spark plug fouling-Colder plug Pre-ignition causing spark plug and/or engine damage-Hotter plug
Spark Plug Inspection
- Inspect the terminal post (1) for damage. Inspect for a bent or broken terminal post (1). Test for a loose terminal post (1) by twisting and pulling the post. The terminal post (1) should NOT move.
- Inspect the insulator (2) for flashover or carbon tracking, soot. This is caused by the electrical charge traveling across the insulator (2) between the terminal post (1) and ground. Inspect for the following conditions: Inspect the spark plug boot for damage. Inspect the spark plug recess area of the cylinder head for moisture, such as oil, coolant or water. A spark plug boot that is saturated causes arcing to ground.
- Inspect the insulator (2) for cracks. All or part of the electrical charge may arc through the crack instead of the electrodes (3, 4).
- Inspect for evidence of improper arcing. Measure the gap between the center electrode (4) and the side electrode (3) terminals. Refer to «Ignition System Specifications»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__ignition-system-specifications) . An excessively wide electrode gap can prevent correct spark plug operation. Inspect for the correct spark plug torque. Refer to «Ignition System Specifications»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__ignition-system-specifications) . Insufficient torque can prevent correct spark plug operation. An over-torqued spark plug causes the insulator (2) to crack. Inspect for signs of tracking that occurred near the insulator tip instead of the center electrode (4). Inspect for a broken or worn side electrode (3). Inspect for a broken, worn or loose center electrode (4) by shaking the spark plug. A rattling sound indicates internal damage. A loose center electrode (4) reduces the spark intensity. Inspect for bridged electrodes (3, 4). Deposits on the electrodes (3, 4) reduce or eliminates the gap. Inspect for worn or missing platinum pads on the electrodes (3, 4), if equipped. Inspect for excess fouling.
- Inspect the spark plug recess area of the cylinder head for debris. Dirty or damaged threads can cause the spark plug not to seat correctly during installation.
Spark Plug Visual Inspection
- Normal operation-Brown to grayish-tan with small amounts of white powdery deposits are normal combustion by-products from fuels with additives.
- Carbon fouled-Dry, fluffy, black carbon or soot caused by the following conditions: Rich fuel mixtures Leaking fuel injectors Excessive fuel pressure Restricted air filter element Incorrect combustion Reduced ignition system voltage output Weak coils Worn ignition wires Incorrect spark plug gap Excessive idling or slow speeds under light loads can keep spark plug temperatures so low that normal combustion deposits may not burn off.
- Deposit fouling-Oil, coolant or additives that include substances such as silicone, very white coating, reduces the spark intensity. Most powdery deposits will not effect spark intensity unless they form into a glazing over the electrode.
- Turn the ignition OFF.
- Remove the ignition coil. Refer to «Ignition Coil(s) Replacement - Bank 1»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) and/or «Ignition Coil(s) Replacement - Bank 2»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Use compressed air in order to remove debris from the spark plug cavity.
- Remove the spark plug.
- Ensure that the spark plug gap is equivalent to the spark plug gap specification. Refer to «Ignition System Specifications»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__ignition-system-specifications) .
- Install the spark plug. Tighten: Tighten the spark plug to 20 N.m (15 lb ft).
- Install the ignition coil. Refer to «Ignition Coil(s) Replacement - Bank 1»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) and/or «Ignition Coil(s) Replacement - Bank 2»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Turn the ignition OFF.
- Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
- Reposition the wiring harness heat shield to obtain access.
- Disconnect the crankshaft position (CKP) electrical connector (3).
- Remove the crankshaft sensor bolt.
- Remove the crankshaft sensor.
- Install the crankshaft position sensor.
- Install the crankshaft position sensor bolt. Tighten: Tighten the crankshaft position sensor bolt to 10 N.m (89 lb in).
- Connect the CKP electrical connector (3).
- Install the wiring harness heat shield to the oil level indicator tube.
- Lower the vehicle.
- Turn the ignition OFF.
- Remove the power steering fluid reservoir bolts and reposition the power steering fluid reservoir in order to provide access. Refer to «Remote Power Steering Fluid Reservoir Replacement»(/buick/lacrosse/i-2004-2009/remont/manual-power-steering/#power-steering-system) in Power Steering System.
- Remove the camshaft position (CMP) sensor electrical connector.
- Remove the CMP sensor bolt.
- Remove the CMP sensor.
- Install the CMP sensor.
- Install the CMP sensor bolt. Tighten: Tighten the CMP sensor bolt to 10 N.m (89 lb in).
- Install the CMP sensor electrical connector.
- Install the power steering fluid reservoir. Refer to «Remote Power Steering Fluid Reservoir Replacement»(/buick/lacrosse/i-2004-2009/remont/manual-power-steering/#power-steering-system) in Power Steering System.
- Turn the ignition OFF.
- Remove the power steering fluid reservoir bolts and reposition the power steering fluid reservoir in order to provide access. Refer to «Remote Power Steering Fluid Reservoir Replacement»(/buick/lacrosse/i-2004-2009/remont/manual-power-steering/#power-steering-system) in Power Steering System.
- Remove the camshaft position (CMP) sensor electrical connector.
- Remove the CMP sensor bolt.
- Remove the CMP sensor.
- Install the CMP sensor.
- Install the CMP sensor bolt. Tighten: Tighten the CMP sensor bolt to 10 N.m (89 lb in).
- Install the CMP sensor electrical connector.
- Install the power steering fluid reservoir. Refer to «Remote Power Steering Fluid Reservoir Replacement»(/buick/lacrosse/i-2004-2009/remont/manual-power-steering/#power-steering-system) in Power Steering System.
- Turn the ignition OFF.
- Remove the ECM bracket bolts and reposition the ECM bracket in order to provide access.
- Remove the camshaft position (CMP) sensor electrical connector.
- Remove the CMP sensor bolt.
- Remove the CMP sensor.
- Install the CMP sensor.
- Install the CMP sensor bolt. Tighten: Tighten the CMP sensor bolt to 10 N.m (89 lb in).
- Install the CMP sensor electrical connector.
- Install the ECM bracket with the ECM. Refer to «Engine Control Module (ECM) Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Turn the ignition OFF.
- Remove the camshaft position (CMP) sensor electrical connector.
- Remove the CMP sensor bolt.
- Remove the CMP sensor.
- Install the CMP sensor.
- Install the CMP sensor bolt. Tighten: Tighten the CMP sensor bolt to 10 N.m (89 lb in).
- Install the CMP sensor electrical connector.
- Turn the ignition OFF.
- Remove the ECM bracket bolts and reposition the ECM bracket in order to provide access.
- Remove the camshaft position (CMP) actuator valve electrical connector.
- Remove the CMP actuator valve bolt.
- Remove the CMP actuator valve.
- Install the CMP actuator valve.
- Install the CMP actuator valve bolt. Tighten: Tighten the CMP actuator valve bolt to 10 N.m (89 lb in).
- Install the CMP actuator valve electrical connector.
- Install the ECM bracket with the ECM. Refer to «Engine Control Module (ECM) Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Turn the ignition OFF.
- Remove the camshaft position (CMP) actuator valve electrical connector.
- Remove the CMP actuator valve bolt.
- Remove the CMP actuator valve.
- Install the CMP actuator valve.
- Install the CMP actuator valve bolt. Tighten: Tighten the CMP actuator valve bolt to 10 N.m (89 lb in).
- Install the CMP valve electrical connector.
- Turn the ignition OFF.
- Remove the power steering fluid reservoir bolts and reposition the power steering fluid reservoir in order to provide access. Refer to «Remote Power Steering Fluid Reservoir Replacement»(/buick/lacrosse/i-2004-2009/remont/manual-power-steering/#power-steering-system) in Power Steering System.
- Remove the camshaft position (CMP) actuator valve electrical connector.
- Remove the CMP actuator valve bolt.
- Remove the CMP actuator valve.
- Install the CMP actuator valve.
- Install the CMP actuator valve bolt. Tighten: Tighten the CMP actuator valve bolt to 10 N.m (89 lb in).
- Install the CMP actuator valve electrical connector.
- Install the power steering fluid reservoir. Refer to «Remote Power Steering Fluid Reservoir Replacement»(/buick/lacrosse/i-2004-2009/remont/manual-power-steering/#power-steering-system) in Power Steering System.
- Turn the ignition OFF.
- Remove the power steering fluid reservoir bolts and reposition the power steering fluid reservoir in order to provide access. Refer to «Remote Power Steering Fluid Reservoir Replacement»(/buick/lacrosse/i-2004-2009/remont/manual-power-steering/#power-steering-system) in Power Steering System.
- Remove the camshaft position (CMP) actuator valve electrical connector.
- Remove the CMP actuator valve bolt.
- Remove the CMP actuator valve.
- Install the CMP actuator valve.
- Install the CMP actuator valve bolt. Tighten: Tighten the CMP actuator valve bolt to 10 N.m (89 lb in).
- Install the CMP actuator valve electrical connector.
- Install the power steering fluid reservoir. Refer to «Remote Power Steering Fluid Reservoir Replacement»(/buick/lacrosse/i-2004-2009/remont/manual-power-steering/#power-steering-system) in Power Steering System.
- Turn the ignition OFF.
- Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
- Reposition the wiring harness heat shield to obtain access.
- Remove the knock sensor (KS) electrical connector.
- Remove the KS bolt.
- Remove the KS.
- Install the KS.
- Install the KS bolt. Tighten: Tighten the KS bolt to 23 N.m (17 lb ft).
- Install the KS electrical connector.
- Install the wiring harness heat shield to the original position.
- Lower the vehicle.
- Turn the ignition OFF.
- Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
- Remove the wiring harness heat shield from the oil level indicator tube to gain access.
- Remove the knock sensor (KS) electrical connector.
- Remove the KS bolt.
- Remove the KS.
- Install the KS.
- Install the KS bolt. Tighten: Tighten the KS bolt to 23 N.m (17 lb ft).
- Install the KS electrical connector.
- Install the wiring harness heat shield to the oil level indicator tube.
- Lower the vehicle.
- Remove the upper intake manifold with the lower intake manifold.
- Remove the intake manifold runner control solenoid bolts.
- Remove the intake manifold runner control solenoid.
- Install the intake manifold runner control solenoid.
- Install the intake manifold runner control solenoid bolts. Tighten: Tighten the intake manifold runner control solenoid bolts to 10 N.m (89 lb in).
- Install the upper intake manifold.
- Remove the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2)
- Remove the air cleaner side cover with the mass air flow (MAF) sensor.
- Remove the filter element (1) from the air cleaner housing (2).
- Install the filter element (1) into the air cleaner housing.
- Install the air cleaner intake duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Install the air cleaner side cover with the MAF sensor.
- Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
- Remove the air inlet duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Remove the air cleaner upper cover bolts and the upper cover.
- Disconnect the mass air flow (MAF) sensor electrical connector.
- Remove and reposition the TCM with the wiring harness in order to gain access.
- Remove the air cleaner bolts and the air cleaner with the MAF sensor.
- Install the air cleaner with the MAF sensor. Install the air cleaner bolts. Tighten: Tighten the air cleaner bolts to 10 N.m (89 lb in).
- Install the TCM with the wiring harness to the air cleaner.
- Connect the MAF sensor electrical connector.
- Install the air cleaner upper cover and the upper cover bolts. Tighten: Tighten the air cleaner upper cover bolts to 4 N.m (35 lb in).
- Install the air inlet duct. Refer to «Air Cleaner Intake Duct Replacement»(/buick/lacrosse/i-2004-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
- Connect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
- Loosen the intake air duct clamps.
- Disconnect the positive crankcase ventilation (PCV) tube from the air intake duct.
- Remove the air intake duct from the throttle body and the mass air flow (MAF) sensor.
- Remove the air intake duct.
- Install the air intake duct to the MAF sensor.
- Install the air cleaner intake duct to the throttle body.
- Connect the PCV tube to the air intake duct.
- Tighten the air intake air duct clamps. Tighten: Tighten the clamps to 2 N.m (18 lb in).
Scheme 28
The engine control module (ECM) (2) interacts with many emission related components and systems and monitors the emission related components and systems for deterioration. OBD II diagnostics monitor the system performance and a diagnostic trouble code (DTC) sets if the system performance degrades.
The malfunction indicator lamp (MIL) operation and the DTC storage are dictated by the DTC type. A DTC is ranked as a Type A or Type B if the DTC is emissions related. Type C is a non-emissions related DTC.
The ECM is in the engine compartment. The ECM is the control center of the engine controls system. The ECM controls the following components
- The fuel injection system
- The ignition system
- The emission control systems
- The on-board diagnostics
- The A/C and fan systems
- The throttle actuation control (TAC) system
The ECM constantly monitors the information from various sensors and other inputs and controls the systems that affect the vehicle performance and the emissions. The ECM also performs diagnostic tests on various parts of the system. The ECM can recognize operational problems and alert the driver via the MIL. When the ECM detects a malfunction, the ECM stores a DTC. The condition area is identified by the particular DTC that is set. This aids the technician in making repairs.
ECM Function
The engine control module (ECM) can supply 5 volts or 12 volts to the various sensors or switches. This is done through pull-up resistors to the regulated power supplies within the ECM. In some cases, even an ordinary shop voltmeter will not give an accurate reading because the resistance is too low. Therefore, a DMM with at least 10 megohms input impedance is required in order to ensure accurate voltage readings.
The ECM controls the output circuits by controlling the ground or the power feed circuit through the transistors or a device called an output driver module.
EEPROM
The electronically erasable programmable read only memory (EEPROM) is a permanent memory that is physically part of the engine control module (ECM). The EEPROM contains program and calibration information that the ECM needs in order to control the powertrain operation.
Special equipment, as well as the correct program and calibration for the vehicle, are required in order to reprogram the ECM.
Theft Deterrent System Frequency Code Programming
This vehicle is equipped with a theft deterrent system which interfaces with the engine control module (ECM). If the ECM is replaced, program the new ECM with the frequency code of the theft deterrent module that is currently on the vehicle. The vehicle will not start until this procedure is completed.
KS Module
The engine control module (ECM) employs an internal integrated circuit to continuously monitor the knock control evaluation circuit. The knock sensor (KS) module contains the circuitry that allows the ECM to utilize the KS signals and diagnose the KS sensors and circuitry. If the ECM detects a fault in the ability of the KS module to sample these signals, a DTC sets.
Data Link Connector (DLC)
The data link connector (DLC) is a 16-pin connector that provides the technician a means of accessing serial data for aid in the diagnosis. This connector allows the technician to use a scan tool in order to monitor the various serial data parameters and display the DTC information. The DLC is located inside of the drivers compartment, underneath the dash.
Malfunction Indicator Lamp (MIL)
The malfunction indicator lamp (MIL) is inside of the instrument panel cluster (IPC). The MIL is controlled by the engine control module (ECM) and illuminates when the ECM detects a condition that affects the vehicle emissions.
ECM Service Precautions
The engine control module (ECM), by design, can withstand the normal current draws that are associated with the vehicle operations. However, care must be used in order to avoid overloading any of these circuits. When testing for opens or shorts, do not ground or apply voltage to any of the ECM circuits unless the diagnostic procedure instructs you to do so. These circuits should only be tested with a DMM.
Emissions Diagnosis For State I/M Programs
This OBD II equipped vehicle is designed to diagnose any conditions that could lead to excessive levels of the following emissions
- Hydrocarbons (HC)
- Carbon monoxide (CO)
- Oxides of nitrogen (NOx)
- Evaporative emission (EVAP) system losses
Should this vehicles on-board diagnostic system (ECM) detect a condition that could result in excessive emissions, the ECM turns ON the malfunction indicator lamp (MIL) and stores a DTC that is associated with the condition.
Aftermarket (Add-On) Electrical And Vacuum Equipment
Note. Do not attach add-on vacuum operated equipment to this vehicle. The use of add-on vacuum equipment may result in damage to vehicle components or systems.
Note. Connect any add-on electrically operated equipment to the vehicle's electrical system at the battery (power and ground) in order to prevent damage to the vehicle.
Aftermarket, add-on, electrical and vacuum equipment is defined as any equipment installed on a vehicle after leaving the factory that connects to the vehicles electrical or vacuum systems. No allowances have been made in the vehicle design for this type of equipment.
Add-on electrical equipment, even when installed to these strict guidelines, may still cause the powertrain system to malfunction. This may also include equipment not connected to the vehicle electrical system, such as portable telephones and radios. Therefore, the first step in diagnosing any powertrain condition is to eliminate all of the aftermarket electrical equipment from the vehicle. After this is done, if the problem still exists, the problem may be diagnosed in the normal manner.
Electrostatic Discharge (ESD) Damage
| IMPORTANT | In order to prevent possible electrostatic discharge damage to the engine control module (ECM), DO NOT touch the connector pins on the ECM. |
The electronic components that are used in the control systems are often designed to carry very low voltage. The electronic components are susceptible to damage caused by electrostatic discharge. Less than 100 volts of static electricity can cause damage to some electronic components. By comparison, it takes as much as 4,000 volts for a person to even feel the zap of a static discharge.
There are several ways for a person to become statically charged. The most common methods of charging are by friction and by induction. An example of charging by friction is a person sliding across a car seat.
Charging by induction occurs when a person with well insulated shoes stands near a highly charged object and momentarily touches ground. Charges of the same polarity are drained off leaving the person highly charged with the opposite polarity. Static charges can cause damage, therefore, it is important to use care when handling and testing electronic components.
Emissions Control Information Label
The underhood Vehicle Emissions Control Information Label contains important emission specifications and setting procedures. In the upper left corner is the exhaust emission information. This identifies the year, the manufacturing division of the engine, the displacement of the engine in liters, the class of the vehicle and type of fuel metering system. There is also an illustrated emission components and vacuum hose schematic.
This label is located in the engine compartment of every General Motors vehicle. If the label has been removed, it can be ordered from GM service parts operations (GMSPO).
Underhood Inspection
| IMPORTANT | This inspection is very important and must be done carefully and thoroughly. |
Perform a careful underhood inspection when performing any diagnostic procedure or diagnosing the cause of an emission test failure. This can often lead to repairing a condition without further steps. Use the following guidelines when performing an inspection
- Inspect all of the vacuum hoses for correct routing, pinches, cuts or disconnects.
- Inspect any hoses that are difficult to see.
- Inspect all of the wires in the engine compartment for the following conditions: Burned or chafed spots Pinched wires Contact with sharp edges Contact with hot exhaust manifolds
Basic Knowledge Required
Note. Lack of basic knowledge of this powertrain when performing diagnostic procedures could result in incorrect diagnostic performance or damage to powertrain components. Do not attempt to diagnose a powertrain problem without this basic knowledge.
A basic understanding of hand tools is necessary in order to effectively use this article of the Service Information.
You must be familiar with some of the basics of engine operation and electrical diagnosis in order to use this article.
- Basic electrical circuits-You should have an understanding of basic electricity and know the meaning of voltage (volts), current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire and you should be able to identify a shorted or open circuit by using a DMM. You should be able to read and understand a wiring diagram.
- Use of digital multimeter-You should be familiar with the DMM, particularly the essential tool. You should be able to use the meter in order to measure the voltage (volts), the resistance (ohms), the current (amps), intermittents (min/max) and frequency (Hertz).
- Use of circuit testing tools-You should not use a test lamp to diagnose the engine controls system unless you are specifically instructed to do so. You should know how to the use jumper wires in order to test the components and allow the DMM readings without damaging the terminals. You should know how to use the J 35616 connector test adapter kit and use the kit whenever the diagnostic procedures call for front probing any connector.
Throttle Actuator Control (TAC) System Description
The throttle actuator control (TAC) system is used to improve emissions, fuel economy and driveability. The TAC system eliminates the mechanical link between the accelerator pedal and the throttle plate. The TAC system eliminates the need for a cruise control module and idle air control motor. The following is a list of TAC system components
- The accelerator pedal assembly includes the following components: The accelerator pedal The accelerator pedal position (APP) sensor 1 The APP sensor 2
- The throttle body assembly includes the following components: The throttle position (TP) sensor 1 The TP sensor 2 The throttle actuator motor The throttle plate
- The engine control module (ECM)
The ECM monitors the driver demand for acceleration with 2 APP sensors. The APP sensor 1 signal voltage range is from about 0.98-4.16 volts as the accelerator pedal is moved from the rest pedal position to the full pedal travel position. The APP sensor 2 range is from about 0.49-2.08 volts as the accelerator pedal is moved from the rest pedal position to the full pedal travel position. The ECM processes this information along with other sensor inputs to command the throttle plate to a certain position.
The throttle plate is controlled with a direct current motor called a throttle actuator control motor. The ECM can move this motor in the forward or reverse direction by controlling battery voltage and/or ground to 2 internal drivers. The throttle plate is held at a 7 percent rest position using a constant force return spring. This spring holds the throttle plate to the rest position when there is no current flowing to the actuator motor.
The ECM monitors the throttle plate angle with 2 TP sensors. The TP sensor 1 signal voltage range is from about 0.5-4.25 volts as the throttle plate is moved from 0 percent to wide open throttle (WOT). The TP sensor 2 voltage range is from about 4.45-0.7 volts as the throttle plate is moved from 0 percent to WOT.
The ECM performs diagnostics that monitor the voltage levels of both APP sensors, both TP sensors and the throttle actuator control motor circuit. It also monitors the spring return rate of both return springs that are housed internal to the throttle body assembly. These diagnostics are performed at different times based on whether the engine is running, not running or whether the ECM is currently in a throttle body relearn procedure.
Every ignition cycle, the ECM performs a quick throttle return spring test to make sure the throttle plate can return to the 7 percent rest position from the 0 percent position. This is to ensure that the throttle plate can be brought to the rest position in case of an actuator motor circuit failure. Observe, under cold conditions, the ECM commands the throttle plate to 7 percent with the ignition ON and the engine OFF to release any ice that may have formed on the throttle plate.
Throttle Body Relearn Procedure
The engine control module (ECM) stores values that include the lowest possible throttle position (TP) sensor positions-0 percent, the rest positions-7 percent and the return rate of both springs. These values will only be erased or overwritten if the ECM is reprogrammed or if a throttle body relearn procedure is performed. Observe, if the battery is disconnected, the ECM will immediately perform a throttle body relearn procedure when the ignition is turned ON.
A throttle body relearn procedure is performed anytime the ignition is turned ON, with the engine OFF for longer than 29 seconds when the following conditions have been met
- The engine speed is less than 40 RPM.
- The vehicle speed is 0 km/h (0 mph).
- The engine coolant temperature (ECT) is between 5-85°C (41-185°F).
- The intake air temperature (IAT) is between than 5-60°C (41-140°F).
- The accelerator pedal position (APP) sensor angle is less than 14.9 percent.
- The ignition 1 voltage is more than 10 volts.
After 29 seconds, the ECM commands the throttle plate from the rest position to full closed, then to around 10 percent open. This procedure takes about 6-8 seconds. If any faults occur in the throttle actuator control (TAC) system, a DTC sets. At the start of this procedure, the scan tool TAC Learn Counter parameter should display 0, then count up to 11 after the procedure is completed. If the counter did not start at 0 or if the counter did not end at 11, a fault has occurred and a DTC should set.
TAC System Default Actions/Reduce Power Modes
There are 2 reduce power modes that the engine control module (ECM) can default to if an error is detected in the throttle actuator control (TAC) system. If an accelerator pedal position (APP) sensor 1 or APP sensor 2 circuit fault, throttle position (TP) sensor 2 circuit fault or if a TP sensor 1 circuit fault is detected with some APP angle, the ECM goes into one of the 2 reduce power modes. In this mode, the engine torque is limited so that the vehicle cannot reach speeds of more than 100 km/h (60 mph). The ECM remains in this reduce power mode during the entire ignition cycle even if the fault is corrected.
If there is a condition with the throttle actuator control circuits, throttle actuator command vs actual position fault, return spring check fault or a TP sensor 1 circuit fault, the ECM goes into the other reduce engine power mode. In this mode, the engine speed is limited to 2,500 RPM and the 3-6 fuel injectors are randomly turned OFF. At this time the Reduced Power indicator is commanded ON. The ECM remains in the reduce power mode during the entire ignition cycle even if the fault is corrected. Observe, if a TP sensor 1 or throttle actuator control circuit fault is present at the time the vehicle is at idle, with no accelerator pedal angle, the engine may stall.
Scheme 29
| Callout | Component Name |
|---|---|
| 1 | Camshaft Actuator Vane |
| 2 | Timing Chain Sprocket |
| 3 | Engine Oil Pressure-For retarding the camshaft |
| 4 | Camshaft |
| 5 | Input Signals from Engine Sensors |
| 6 | Engine Control Module (ECM) |
| 7 | Camshaft Actuator Solenoid |
| 8 | Engine Oil Pump |
| 9 | Engine Oil Pressure Supply |
| 10 | Engine Oil Drain |
| 11 | Engine Oil Pressure-For advancing the camshaft |
| 12 | Camshaft Actuator Rotor |
| 13 | Camshaft Position Sensor Reluctor |
| 14 | Camshaft Actuator Lock Pin |
| 15 | Camshaft Actuator Housing |
The camshaft actuator system enables the engine control module (ECM) to change camshaft timing of all 4 camshafts while the engine is operating. The CMP actuator assembly (15) varies the camshaft position in response to directional changes in oil pressure. The CMP actuator solenoid valve controls the oil pressure that is applied to advance or retard a camshaft. Modifying camshaft timing under changing engine demand provides better balance between the following performance concerns
- Engine power output
- Fuel economy
- Lower tailpipe emissions
The CMP actuator solenoid valve (7) is controlled by the ECM. The crankshaft position (CKP) sensor and the CMP sensors are used to monitor changes in camshaft positions. The ECM uses the following information in order to calculate the desired camshaft positions
- The engine coolant temperature (ECT) sensor
- The calculated engine oil temperature (EOT)
- The mass air flow (MAF) sensor
- The throttle position (TP) sensor
- The vehicle speed sensor (VSS)
- The volumetric efficiency
Operation
The CMP actuator assembly has an outer housing that is driven by an engine timing chain. Inside the assembly is a rotor with fixed vanes that is attached to the camshaft. Oil pressure that is applied to the fixed vanes will rotate a specific camshaft in relationship to the crankshaft. The movement of the intake camshafts will advance the intake valve timing up to a maximum of 50 crankshaft degrees. The movement of the exhaust camshafts will retard the exhaust valve timing up to a maximum of 50 crankshaft degrees. When oil pressure is applied to the return side of the vanes, the camshafts will return to 0 crankshaft degrees or top dead center (TDC). The CMP actuator solenoid valve directs the oil flow that controls the camshaft movement. The ECM commands the CMP solenoid to move the solenoid plunger and spool valve until oil flows from the advance passage (11). Oil flowing thru the CMP actuator assembly from the CMP solenoid advance passage applies pressure to the advance side of the vanes in the CMP actuator assembly. When the camshaft position is retarded, the CMP actuator solenoid valve directs oil to flow into the CMP actuator assembly from the retard passage (3). The ECM can also command the CMP actuator solenoid valve to stop oil flow from both passages in order to hold the current camshaft position.
The ECM operates the CMP actuator solenoid valve by pulse width modulation (PWM) of the solenoid coil. The higher the PWM duty cycle, the larger the change in camshaft timing. The CMP actuator assembly also contains a lock pin (14) that prevents movement between the outer housing and the rotor vane assembly. The lock pin is released by oil pressure before any movement in the CMP actuator assembly takes place. The ECM is continuously comparing CMP sensor inputs with CKP sensor input in order to monitor camshaft position and detect any system malfunctions. If a condition exists in either the intake or exhaust camshaft actuator system, the opposite bank, intake or exhaust, camshaft actuator will default to 0 crankshaft degrees.
| Driving Condition | Change in Camshaft Position | Objective | Result |
|---|---|---|---|
| Idle | No Change | Minimize Valve Overlap | Stabilize Idle Speed |
| Light Engine Load | Retard Valve Timing | Decrease Valve Overlap | Stable Engine Output |
| Medium Engine Load | Advance Valve Timing | Increase Valve Overlap | Better Fuel Economy with Lower Emissions |
| Low to Medium RPM with Heavy Load | Advance Valve Timing | Advance Intake Valve Closing | Improve Low to Mid-range Torque |
| High RPM with Heavy Load | Retard Valve Timing | Retard Intake Valve Closing | Improve Engine Output |
CMP Actuator System Operation
Fuel System Overview
The fuel system is a returnless on-demand design. The fuel pressure regulator is a part of the fuel sender assembly, eliminating the need for a return pipe from the engine. A returnless fuel system reduces the internal temperature of the fuel tank by not returning hot fuel from the engine to the fuel tank. Reducing the internal temperature of the fuel tank results in lower evaporative emissions.
The fuel tank stores the fuel supply. An electric turbine style fuel pump attaches to the fuel sender assembly inside the fuel tank. The fuel pump supplies high pressure fuel through the fuel filter contained in the fuel sender assembly and the fuel feed pipe to the Fuel Injection System. The fuel pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pump also supplies fuel to a venturi pump located on the bottom of the fuel sender assembly. The function of the venturi pump is to fill the fuel sender assembly reservoir. The fuel pressure regulator, a part of the fuel sender assembly, maintains the correct fuel pressure to the fuel injection system. The fuel pump and sender assembly contains a reverse flow check valve. The check valve and the fuel pressure regulator maintain fuel pressure in the fuel feed pipe and the fuel rail in order to prevent long cracking times.
Fuel Tank
The fuel tank stores the fuel supply. The fuel tank is located in the rear of the vehicle. The fuel tank is held in place by 2 metal straps that attach to the frame. The fuel tank is molded from high-density polyethylene.
Scheme 30
The fuel fill pipe has a built-in restrictor in order to prevent refueling with leaded fuel.
Scheme 31
| Callout | Component Name |
|---|---|
| 1 | Fuel Tank Filler Cap |
| 2 | Fuel Tank Filler Pipe |
| 3 | Fuel Filler Door |
Note. Use a fuel tank filler pipe cap with the same features as the original when a replacement is necessary. Failure to use the correct fuel tank filler pipe cap can result in a serious malfunction of the fuel system.
The fuel tank filler pipe is equipped with a turn to vent screw on the type cap which incorporates a ratchet action in order to prevent over-tightening.
The turn to vent feature allows the fuel tank pressure relief prior to removal. Instructions for proper use are imprinted on the cap cover. A vacuum safety relief valve is incorporated into this cap.
The fuel fill pipe has a tethered fuel filler cap. A torque-limiting device prevents the cap from being over-tightened. To install the cap, turn the cap clockwise until you hear audible clicks. This indicates that the cap is correctly torqued and fully seated. A fuel filler cap that is not fully seated may cause a malfunction in the emission system.
Scheme 32
| Callout | Component Name |
|---|---|
| 1 | Fill Limit Vent Valve (FLVV) |
| 2 | T-Connector for Vapor Hose/Pipes to Vent/Rollover Valve and Fill Tube |
| 3 | Fuel Tank Pressure (FTP) Sensor |
| 4 | FLVV Outlet to Evaporative Emission (EVAP) Canister |
| 5 | Fuel Feed Outlet |
| 6 | Fuel Return Inlet-Not Used |
| 7 | Fuel Sender Assembly Connector |
| 8 | Fuel Pump |
| 9 | Fuel Pressure Regulator |
| 10 | Fuel Filter Assembly |
| 11 | Fuel Level Sensor Float |
Scheme 33
The fuel level sensor consists of a float, a wire float arm and a ceramic resistor card. The position of the float arm indicates the fuel level. The fuel level sensor contains a variable resistor which changes resistance in correspondence with the position of the float arm. The control module sends the fuel level information to the instrument panel cluster (IPC). This information is used for the IPC fuel gage and the low fuel warning indicator, if applicable. The control module also monitors the fuel level input for various diagnostics.
Fuel Pump
The fuel pump is mounted in the fuel sender assembly reservoir. The fuel pump is an electric high-pressure pump. Fuel is pumped to the fuel injection system at a specified flow and pressure. The fuel pump delivers a constant flow of fuel to the engine even during low fuel conditions and aggressive vehicle maneuvers. The control module controls the electric fuel pump operation through a fuel pump relay. The fuel pump flex pipe acts to dampen the fuel pulses and noise generated by the fuel pump.
Fuel Sender Strainers
The strainers act as a coarse filter to perform the following functions
- Filter contaminants
- Separate water from fuel
- Provide a wicking action that helps draw fuel into the fuel pump
Fuel stoppage at the strainer indicates that the fuel tank contains an abnormal amount of sediment or water. Therefore, the fuel tank will need to be removed and cleaned and the filter strainer should be replaced.
Fuel Filter
The fuel filter is contained in the fuel sender assembly inside the fuel tank. The paper filter element traps particles in the fuel that may damage the fuel injection system. The filter housing is made to withstand maximum fuel system pressure, exposure to fuel additives and changes in temperature. There is no service interval for fuel filter replacement.
Scheme 34
The fuel pressure regulator (2) is contained in the fuel sender assembly. The fuel pressure regulator is a diaphragm relief valve. The diaphragm has fuel pressure on one side and regulator spring pressure on the other side. A software bias compensates the injector on-time because the fuel pressure regulator is not referenced to the manifold vacuum. The fuel pressure regulator keeps fuel available to the injectors at a regulated pressure.
On-Board Refueling Vapor Recovery (ORVR) System
The on-board refueling vapor recovery (ORVR) system is an on-board vehicle system to recover fuel vapors during the vehicle refueling operation. The flow of liquid fuel down to the fuel tank filler neck provides a liquid seal. The purpose of ORVR is to prevent refueling vapor from exiting the fuel tank filler neck. The ORVR components are listed below, with a brief description of their operation
- The fuel tank-The fuel tank contains the modular fuel sender, the fuel limiter vent valve (FLVV) and 1 rollover valve.
- The fuel filler pipe-The fuel filler pipe carries fuel from the fuel nozzle to the fuel tank.
- The evaporative emission (EVAP) canister-The EVAP canister receives refueling vapor from the fuel system, stores the vapor and releases the vapor to the engine upon demand.
- The vapor lines-The vapor lines transport fuel vapor from the tank assembly to the EVAP canister and engine.
- The check valve-The check valve limits fuel spit-back from the fuel tank during the refueling operation by allowing fuel flow only into the fuel tank. The check valve is located at the bottom of the fuel filler pipe.
- The modular fuel sender assembly-The modular fuel sender assembly pumps fuel to the engine from the fuel tank.
- The fuel tank pressure (FTP) sensor is located on top of the fuel tank vapor dome.
- The FLVV-The FLVV acts as a shut-off valve. The FLVV is located in the fuel tank. This valve has the following functions: Controlling the fuel tank fill level by closing the primary vent from the fuel tank Preventing fuel from exiting the fuel tank via the vapor line to the canister Providing fuel spillage protection in the event of a vehicle rollover by closing the vapor path from the tank to the engine
- The pressure vacuum relief valve-The pressure vacuum relief valve provides venting of excessive fuel tank pressure and vacuum. The valve is located in the fuel fill cap.
- The vapor recirculation line-The vapor recirculation line is used to transport vapor from the fuel tank to the top of the fill pipe during refueling to reduce vapor loading to the enhanced EVAP canister.
Fuel Feed Pipes
The fuel feed pipe carries fuel from the fuel tank to the fuel injection system.
Nylon Fuel Pipes
Nylon pipes are constructed to withstand maximum fuel system pressure, exposure to fuel additives and changes in temperature. There are 2 sizes of nylon pipes used
- 9.53 mm (3/8 in) ID for the fuel feed
- 12.7 mm (1/2 in) ID for the vent
Heat resistant rubber hose or corrugated plastic conduit protect the sections of the pipes that are exposed to chafing, high temperature or vibration.
Nylon fuel pipes are somewhat flexible and can be formed around gradual turns under the vehicle. However, if nylon fuel pipes are forced into sharp bends, the pipes kink and restrict the fuel flow. Also, once exposed to fuel, nylon pipes may become stiffer and are more likely to kink if bent too far. Take special care when working on a vehicle with nylon fuel pipes.
Quick-Connect Fittings
Quick-connect fittings provide a simplified means of installing and connecting fuel system components. The fittings consist of a unique female connector and a compatible male pipe end. O-rings, located inside the female connector, provide the fuel seal. Integral locking tabs inside the female connector hold the fittings together.
Fuel Pipe O-Rings
O-rings seal the threaded connections in the fuel system. The fuel system O-ring seals are made of special material. Service the O-ring seals with the correct service part.
Fuel Rail
The fuel rail consists of 3 parts
- The pipe that carries fuel to each injector
- The fuel pressure test port
- Six individual fuel injectors
The fuel rail is mounted on the intake manifold and distributes the fuel to each cylinder through the individual injectors.
Fuel Injectors
The fuel injector is a solenoid device that is controlled by the engine control module (ECM). When the ECM energizes the injector coil, a normally closed ball valve opens, allowing the fuel to flow past a director plate to the injector outlet. The director plate has holes that control the fuel flow, generating a dual conical spray pattern of finely atomized fuel at the injector outlet. The fuel from the outlet is directed at both of the intake valves, causing the fuel to become further vaporized before entering the combustion chamber.
The fuel injectors will cause various driveability conditions if the following conditions occur
- If the injectors will not open
- If the injectors are stuck open
- If the injectors are leaking
- If the injectors have a low coil resistance
Fuel Pump Relay
The fuel pump relay allows the engine control module (ECM) to energize the fuel pump. The ECM enables the fuel pump whenever the crankshaft position (CKP) sensor pulses are detected.
Engine Fueling
The engine is fueled by six individual injectors, one for each cylinder, that are controlled by the engine control module (ECM). The ECM controls each injector by energizing the injector coil for a brief period once every other engine revolution. The length of this brief period or pulse, is carefully calculated by the ECM to deliver the correct amount of fuel for proper driveability and emissions control. The period of time when the injector is energized is called the pulse width and is measured in milliseconds, thousandths of a second.
While the engine is running, the ECM is constantly monitoring the inputs and recalculating the appropriate pulse width for each injector. The pulse width calculation is based on the injector flow rate, mass of fuel the energized injector will pass per unit of time, the desired air/fuel ratio and actual air mass in each cylinder and is adjusted for battery voltage, short term and long term fuel trim. The calculated pulse is timed to occur as each cylinders intake valves are closing to attain largest duration and most vaporization.
Fueling during a crank is slightly different than fueling during an engine run. As the engine begins to turn, a prime pulse may be injected to speed starting. As soon as the ECM can determine where in the firing order the engine is, the ECM begins pulsing the injectors. The pulse width during the crank is based on the coolant temperature and the engine load.
The fueling system has several automatic adjustments in order to compensate for the differences in the fuel system hardware, the driving conditions, the fuel used and the vehicle aging. The basis for the fuel control is the pulse width calculation that is described above. Included in this calculation are an adjustment for the battery voltage, the short term fuel trim and the long term fuel trim. The battery voltage adjustment is necessary since the changes in the voltage across the injector affect the injector flow rate. The short term and the long term fuel trims are fine and gross adjustments to the pulse width that are designed in order to maximize the driveability and emissions control. These fuel trims are based on the feedback from the oxygen sensors in the exhaust stream and are only used when the fuel control system is in a Closed Loop operation.
Under certain conditions, the fueling system will turn OFF the injectors for a period of time. This is referred to as fuel shut-off. Fuel shut-off is used in order to improve traction, save fuel, improve emissions and protect the vehicle under certain extreme or abusive conditions.
In case of a major internal problem, the ECM may be able to use a back-up fuel strategy for limp in mode that will run the engine until service can be performed.
Sequential Fuel Injection (SFI)
The engine control module (ECM) controls the fuel injectors based on information that the ECM receives from several information sensors. Each injector is fired individually in the engine firing order, which is called sequential fuel injection. This allows precise fuel metering to each cylinder and improves the driveability under all of the driving conditions.
The ECM has several operating modes for fuel control, depending on the information that has been received from the sensors.
Starting Mode
When the engine control module (ECM) detects reference pulses from the crankshaft position (CKP) sensor, the ECM will enable the fuel pump. The fuel pump runs and builds up pressure in the fuel system. The ECM then monitors the mass air flow (MAF), intake air temperature (IAT), engine coolant temperature (ECT) and the throttle position (TP) sensor signal in order to determine the required injector pulse width for starting.
Clear Flood Mode
If the engine is flooded with fuel during starting and will not start, the Clear Flood Mode can be manually selected. To select Clear Flood Mode, push the accelerator to wide open throttle (WOT). With this signal, the engine control module (ECM) will completely turn OFF the injectors and will maintain this stage as long as the ECM indicates a WOT condition with engine speed below a predetermined value.
Run Mode
The Run Mode has 2 conditions: Open Loop operation and Closed Loop operation. When the engine is first started and the engine speed is more than a predetermined value, the system goes into Open Loop operation. In Open Loop operation, the engine control module (ECM) ignores the signals from the oxygen sensors and calculates the required injector pulse width based primarily on inputs from the mass air flow (MAF), intake air temperature (IAT) and engine coolant temperatures (ECT) sensors.
In Closed Loop, the ECM adjusts the calculated injector pulse width for each bank of injectors based on the signals from each oxygen sensor.
Acceleration Mode
The engine control module (ECM) monitors the changes in the throttle position (TP) and the mass air flow (MAF) sensor signals in order to determine when the vehicle is being accelerated. The ECM will then increase the injector pulse width in order to provide more fuel for improved performance.
Deceleration Mode
The engine control module (ECM) monitors changes in throttle position (TP) and mass air flow (MAF) sensor signals to determine when the vehicle is being decelerated. The ECM will then decrease injector pulse width or even shut OFF injectors for short periods to reduce exhaust emissions and for better (engine braking) deceleration.
Battery Voltage Correction Mode
The engine control module (ECM) can compensate in order to maintain acceptable vehicle driveability when the ECM sees a low battery voltage condition. The ECM compensates by performing the following functions
- Increasing the injector pulse width in order to maintain the proper amount of fuel being delivered
- Increasing the idle speed to increase the generator output
Fuel Shut-Off Mode
The engine control module (ECM) has the ability to completely turn OFF all of the injectors or selectively turn OFF some of the injectors when certain conditions are met. These fuel shut-off modes allow the ECM to protect the engine from damage and also to improve the vehicles driveability.
The ECM will disable all of the six injectors under the following conditions
- Ignition OFF-Prevents engine run-on
- Ignition ON but no crank position (CKP) signal-Prevents flooding or backfiring
- A high engine speed-Above the red line
- A high vehicle speed-Above the rated tire speed
- Closed throttle cast down-Reduces the emissions and increases engine braking.
The ECM will selectively disable the injectors under the following conditions
- The torque management enabled-Transmission shifts or abusive maneuvers.
- The traction control enabled-In conjunction with the front brakes applying
EVAP System Operation
The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister. Carbon in the canister absorbs and stores the fuel vapors. Excess pressure is vented through the vent line and EVAP vent valve to atmosphere. The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the control module will command the EVAP purge valve ON, open, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent valve OFF, open, fresh air will be drawn through the valve and vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge valve into the intake manifold to be consumed during normal combustion. The control module uses several tests to determine if the EVAP system is leaking.
Large Leak Test
This tests for large leaks and blockages in the EVAP system. The control module will command the EVAP vent valve ON, closed and command the EVAP purge valve ON, open, with the engine running, allowing engine vacuum into the EVAP system. The control module monitors the fuel tank pressure (FTP) sensor voltage to verify that the system is able to reach a predetermined level of vacuum within a set amount of time. The control module then commands the EVAP purge valve OFF, closed, sealing the system and monitors the vacuum level for decay. If the control module does not detect that the predetermined vacuum level was achieved or the vacuum decay rate is more than a calibrated level on 2 consecutive tests, DTC P0455 sets.
Small Leak Test
The engine off natural vacuum, (EONV), diagnostic is the small leak detection diagnostic for the EVAP system. The EONV diagnostic monitors the EVAP system pressure or vacuum with the key OFF. The EONV utilizes the temperature changes and the resulting naturally occurring vacuum or pressure in the fuel tank immediately following a drive cycle. When the vehicle is driven, the temperature in the fuel tank rises. When the vehicle is parked with the engine OFF and key OFF, the temperature in the fuel tank will continue to rise for a period of time and then begin to decrease. The EONV diagnostic relies on this temperature change and the corresponding pressure change to determine if an EVAP system leak is present. The EONV diagnostic is designed to detect leaks as small as 0.51 mm (0.020 in). The diagnostic can determine if a small leak is present based on vacuum or pressure readings in the EVAP system. When the EVAP system is sealed a finite amount of pressure or vacuum will be observed. When a 0.51 mm (0.020 in) leak is present, little or no pressure or vacuum is observed. If the test reports a failing value, DTC P0442 will set.
Canister Vent Restriction Test
If the EVAP vent system is restricted, fuel vapors will not be properly purged from the EVAP canister. The control module tests this by commanding the EVAP purge valve ON, open; and commanding the EVAP vent valve OFF, open; and monitoring the FTP sensor for an increase in vacuum. If vacuum increases more than a calibrated value, DTC P0446 sets.
Purge Valve Leak Test
If the EVAP purge valve does not seal properly, fuel vapors could enter the engine at an undesired time, causing driveability concerns. The control module tests for this by commanding the EVAP purge valve OFF, closed; and vent valve ON, closed; sealing the system and monitoring the FTP for an increase in vacuum. If the control module detects that EVAP system vacuum increases above a calibrated value, DTC P0496 sets.
EVAP System Components
The EVAP system consists of the following components
EVAP Canister
The canister is filled with carbon pellets used to absorb and store fuel vapors. Fuel vapor is stored in the canister until the control module determines that the vapor can be consumed in the normal combustion process.
EVAP Purge Valve
The EVAP purge valve controls the flow of vapors from the EVAP system to the intake manifold. This normally closed valve is pulse width modulated (PWM) by the control module to precisely control the flow of fuel vapor to the engine. The valve will also be opened during some portions of the EVAP testing, allowing engine vacuum to enter the EVAP system.
EVAP Vent Valve
The EVAP vent valve controls fresh airflow into the EVAP canister. The valve is normally open. The control module will command the valve closed during some EVAP tests, allowing the system to be tested for leaks.
Fuel Tank Pressure Sensor
The FTP sensor measures the difference between the pressure or vacuum in the fuel tank and outside air pressure. The control module provides a 5-volt reference and a ground to the FTP sensor. The FTP sensor provides a signal voltage back to the control module that can vary between 0.1-4.9 volts. As FTP increases, FTP sensor voltage decreases, high pressure = low voltage. As FTP decreases, FTP voltage increases, low pressure or vacuum = high voltage.
EVAP Service Port
The EVAP service port is located in the EVAP purge pipe between the EVAP purge valve and the EVAP canister. The service port is identified by a green colored cap.
Electronic Ignition (EI) System Description
The electronic ignition (EI) system produces and controls a high-energy secondary spark. This spark is used to ignite the compressed air/fuel mixture at precisely the correct time. This provides optimal performance, fuel economy and control of exhaust emissions. This ignition system uses an individual coil for each cylinder. The ignition coils are mounted in the center of each camshaft cover with short integrated boots connecting the coils to the spark plugs. The driver modules within each ignition coil are commanded ON/OFF by the engine control module (ECM). The ECM primarily uses engine speed, the MAF sensor signal and position information from the crankshaft position (CKP) and the camshaft position (CMP) sensors. This controls the sequence, dwell and timing of the spark. The EI system consists of the following components
Crankshaft Position (CKP) Sensor
The crankshaft position (CKP) sensor works in conjunction with a 58 tooth reluctor wheel on the crankshaft. The engine control module (ECM) monitors the voltage between the CKP sensor signal circuits. As each reluctor wheel tooth rotates past the sensor, the sensor creates an analog signal. This analog signal is processed by the ECM. The reluctor wheel teeth are 6 degrees apart. Having only 58 teeth leaves a 12 degree span that is uncut. This creates a signature pattern that enables the ECM to determine the CKP. The ECM can determine which pair of cylinders is approaching top dead center based on the CKP signal alone. The camshaft position (CMP) sensor signals are used in order to determine which of these 2 cylinders is on a firing stroke and which is on the exhaust stroke. The ECM uses this to properly synchronize the ignition system, the fuel injectors and the knock control. This sensor is also used in order to detect misfire.
Camshaft Position (CMP) Sensor
This engine uses 4 camshaft position (CMP) sensors, one for each camshaft. The CMP sensor signals are a digital ON/OFF pulse, output 4 times per revolution of the camshaft. The CMP sensor does not directly affect the operation of the ignition system. The CMP sensor information is used by the engine control module (ECM) to determine the position of the 4 camshafts relative to the crankshaft position. By monitoring the CMP and crankshaft position (CKP) signals the ECM can accurately time the operation of the fuel injectors. The ECM supplies the CMP sensor with a 5-volt reference circuit and a low reference circuit. The CMP sensor signals are an input to the ECM. These signals are also used to detect camshaft alignment with the crankshaft.
Ignition Coils
Each ignition coil contains a solid state driver module as its primary element. The engine control module (ECM) signals the coil driver to initiate a firing event by applying ignition control (IC) circuit voltage for the appropriate time or dwell. When the voltage is removed the coil fires the spark plug. The ignition coils use the following circuits
- An ignition 1 voltage supply circuit
- An IC circuit
- Two ground circuits
Engine Control Module (ECM)
The engine control module (ECM) controls all ignition system functions and constantly corrects the spark timing. The ECM monitors information from various sensor inputs that include the following components
- The throttle position (TP) sensor
- The engine coolant temperature (ECT) sensor
- The mass air flow (MAF) sensor
- The intake air temperature (IAT) sensor
- The vehicle speed sensor (VSS)
- The transmission gear position or range information sensors
- The engine knock sensors (KS)
- Ambient pressure sensor (BARO)
Knock Sensor (KS) System Description
You can diagnose all of the sensors and most of the input circuits with a scan tool. Within this article is a short description of how to use a scan tool wherever possible to diagnose these circuits. You can also use the scan tool to compare the values for an engine that is running normally with the engine you are diagnosing.
The knock sensor (KS) system detects engine knocking or pinging. The ECM will retard the spark timing based on the signals from the KS system. The KS produce an AC voltage that is sent to the engine control module (ECM). The amount of the AC voltage produced is proportional to the amount of knock.
The ECM monitors the voltage of the sensors after each cylinder has fired.
If knock occurs in any of the cylinders, the ignition will be retarded for that particular cylinder. If the knocking then stops, the ignition will be restored to what it was before in steps.
Should knocking continue in the same cylinder in spite of the ignition being retarded, the ECM will retard the ignition an additional steps and so on, up to a maximum of 12 degrees of retard. The ignition will also be retarded at high ambient temperatures in order to counteract knocking tendencies provoked by high intake air temperatures.
Should either bank 1 or bank 2 sensor fail to work or should an internal circuit problem occur, the ignition timing will then use a default strategy. The default strategy will retard the ignition the maximum allowed amount to protect the engine from possible damage.
Scheme 35
| Callout | Component Name |
|---|---|
| 1 | Electrical Connector |
| 2 | MAF Sensor |
| 3 | Circuit Board Cover |
| 4 | Circuit Board |
| 5 | IAT Sensor |
| 6 | Circuitry Housing |
The mass air flow (MAF) sensor measures the amount of air coming into the engine. This direct airflow measurement is more accurate than the calculated airflow information obtained from the other sensor inputs. The MAF sensor also houses an integrated intake air temperature (IAT) sensor. The MAF sensor uses the following circuits
- An ignition 1 voltage circuit
- A 5-volt reference circuit
- A low reference circuit
- A signal circuit
- IAT signal circuit
The MAF sensor that is used on this vehicle is a hot film type and is used in order to measure the air flow rate. The MAF output voltage is a function of the power required to keep the air flow sensing elements at a fixed temperature above the ambient temperature. The air flowing through the sensor cools the sensing elements. The amount of cooling is proportional to the amount of air flow. As the air flow increases, more current is needed in order to maintain the hot film at a constant temperature. The MAF sensor converts the changes in the current draw to a voltage signal that the engine control module (ECM) monitors. The ECM calculates the air flow based on this signal.
The ECM monitors the MAF sensor signal voltage and can determine if the sensor signal voltage is too low or too high. The ECM can also detect airflow that is inappropriate for a given operating condition based on the signal voltage.
The scan tool displays the MAF value and displays the value in grams per second (g/s). Values should change rather quickly on acceleration, but should remain fairly stable at any given engine speed. If the ECM detects a condition with the MAF sensor circuits, the following DTCs set
- P0101 Mass Air Flow (MAF) Sensor Performance
- P0102 Mass Air Flow (MAF) Sensor Circuit Low Voltage
- P0103 Mass Air Flow (MAF) Sensor Circuit High Voltage
Special Tools
Special Tools Illustration Tool Number/Description EL 39021-460 Fuel Injector Test Adapter GE 41415-50 Fuel Tank Cap Adapter J 26792 HEI Spark Tester J 34730-1A Fuel Pressure Gage J 34730-405 Injector Test Lamp J 35616 GM-Approved Terminal Test Kit J 35616-200 Test Light - Probe Kit J 37088-A Fuel Line Disconnect Tool Set J 37287 Fuel Line Shut-Off Adapters J 39021 Fuel Injector Coil and Balance Test J 39021-210 Injector Selector Switch Box J 41413-200 Evaporative Emission System Tester (EEST) J 41413-SPT High Intensity White Light J 41413-VLV EVAP Pressure and Purge Station J 42598-B CAN+ Vehicle Data Recorder J 42960-02 Fuel Flapper Door Holder J 43244 Relay Puller Pliers J 44175 Fuel Composition Tester J 44581 Fuel Line Disconnect Tool J 44602 Injector Test Adapter J 45004 Fuel Tank Drain Hose J 45722 Fuel Sender Lock Ring Wrench
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See also:
• DTC P0008
• DTC P0135
• DTC P0442
• DTC P167A
• DTC P2231
• Electrical Center Identification Views
• Battery Negative Cable Disconnect/Connect Procedure (L26)
• Fastener Notice
• Control Module References
• Draining and Filling Cooling System (L26 Static Fill)
• Lifting and Jacking the Vehicle
• Closeout/Insulator Panel Replacement - Left
• Gasoline/Gasoline Vapors Caution
• COVER AND PLUG OPENINGS NOTICE
• Fuel Pressure Relief Procedure
• Fuel Tank Draining Procedure
• Quick Connect Fitting(s) Service (Plastic Collar)
• Fuel Injector Sight Shield Replacement
• Intake Manifold Replacement - Upper
• Safety Glasses and Compressed Air Caution
• Remote Power Steering Fluid Reservoir Replacement
• Air Cleaner Intake Duct Replacement
• Special Tools
• Ignition System Specifications