Engine Control System - 4.6l (lh2) - Introduction

Temperature vs Resistance

°C	°F	OHMS
Temperature vs Resistance Values (Approximate)
150	302	47
140	284	60
130	266	77
120	248	100
110	230	132
100	212	177
90	194	241
80	176	332
70	158	467
60	140	667
50	122	973
45	113	1188
40	104	1459
35	95	1802
30	86	2238
25	77	2796
20	68	3520
15	59	4450
10	50	5670
5	41	7280
0	32	9420
5	23	12300
10	14	16180
15	5	21450
20	4	28680
30	22	52700
40	40	100700

Temperature vs Resistance

Altitude vs Barometric Pressure

Altitude Measured in Meters (m)	Altitude Measured in Feet (ft)	Barometric Pressure Measured in Kilopascals (kPa)
Determine your altitude by contacting a local weather station or by using another reference source.
4 267	14,000	56-64
3 962	13,000	58-66
3 658	12,000	61-69
3 353	11,000	64-72
3 048	10,000	66-74
2 743	9,000	69-77
2 438	8,000	71-79
2 134	7,000	74-82
1 829	6,000	77-85
1 524	5,000	80-88
1 219	4,000	83-91
914	3,000	87-95
610	2,000	90-98
305	1,000	94-102
0	0 Sea Level	96-104
305	1,000	101-105

Altitude vs Barometric Pressure

Ignition System Specifications

Application	Specification
Application	Metric	English
Ignition Type	Module/Coil Per Cylinder
Firing Order	1-2-7-3-4-5-6-8
Primary Coil Current	10 Amps
Spark Plug Torque	20 N.m	15 lb ft
Spark Plug Gap	1.02 mm	0.040 in
Spark Plug Type	GM 12571533

Ignition System Specifications

Fastener Tightening Specifications

Application	Specification
Application	Metric	English
Accelerator Pedal Position (APP) Sensor Bolt	9 N.m	80 lb in
Air Cleaner Assembly Bolts	10 N.m	89 lb in
Air Cleaner Assembly Cover Screws	3 N.m	27 lb in
Air Cleaner Outlet Duct Clamps	3 N.m	27 lb in
Camshaft Position (CMP) Actuator Solenoid Bolt	8 N.m	71 lb in
Camshaft Position (CMP) Sensor Bolt	10 N.m	89 lb in
Crankshaft Position (CKP) Sensor Bolt	10 N.m	89 lb in
Engine Control Module (ECM) Nut	8 N.m	71 lb in
Engine Coolant Temperature (ECT) Sensor	20 N.m	15 lb ft
Evaporative Emission (EVAP) Canister Nut	6 N.m	53 lb in
Evaporative Emission (EVAP) Canister Purge Valve Bolt	12 N.m	106 lb in
Fuel Filler Tube Bolt	3.5 N.m	31 lb in
Fuel Filler Tube Brace Bolt	9 N.m	80 lb in
Fuel Filler Tube Hose Clamp	3.5 N.m	31 lb in
Fuel Filter Bracket Bolt	9 N.m	80 lb in
Fuel Filter Outlet Fitting	30 N.m	22 lb ft
Fuel Injector Sight Shield Bracket Nut	10 N.m	89 lb in
Fuel Rail Stud	10 N.m	89 lb in
Fuel Tank Strap Bolt	50 N.m	37 lb ft
Heated Oxygen Sensor (HO2S)	42 N.m	31 lb ft
Ignition Coil Bolt	10 N.m	89 lb in
Ignition Module Assembly Bolt	10 N.m	89 lb in
Knock Sensor (KS) Bolt	20 N.m	15 lb ft
Lower Shock Bolt	150 N.m	111 lb ft
Manifold Absolute Pressure (MAP) Sensor Bracket Bolt	12 N.m	106 lb in
Mass Air Flow Sensor Screw	4 N.m	35 lb in
Rear Frame Bolt	265 N.m	195 lb ft
Spark Plug	20 N.m	15 lb ft
Throttle Body Bolt	10 N.m	89 lb in
Transmission Support Bolt	60 N.m	44 lb ft

Fastener Tightening Specifications

Action Taken When the DTC Sets - Type A

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

Action Taken When the DTC Sets - Type B

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

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

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

Conditions for Clearing the DTC - Type X

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

Diagnostic Trouble Code (DTC) Type(s)

Diagnostic Trouble Code (DTC)	Domestic/Export
DTC P0010	B
DTC P0011	A
DTC P0013	B
DTC P0014	A
DTC P0016	A
DTC P0017	A
DTC P0018	A
DTC P0019	A
DTC P0020	B
DTC P0021	A
DTC P0023	B
DTC P0024	A
DTC P0030	B
DTC P0031	B
DTC P0032	B
DTC P0036	B
DTC P0037	B
DTC P0038	B
DTC P0050	B
DTC P0051	B
DTC P0052	B
DTC P0056	B
DTC P0057	B
DTC P0058	B
DTC P0068	B
DTC P0101	B
DTC P0102	B
DTC P0103	B
DTC P0106	B
DTC P0107	B
DTC P0108	B
DTC P0112	B
DTC P0113	B
DTC P0116	B
DTC P0117	B
DTC P0118	B
DTC P0122	A
DTC P0123	A
DTC P0125	B
DTC P0128	B
DTC P0131	B
DTC P0132	B
DTC P0133	B
DTC P0135	B
DTC P0137	B
DTC P0138	B
DTC P0139	B
DTC P0140	B
DTC P0141	B
DTC P0151	B
DTC P0152	B
DTC P0153	B
DTC P0155	B
DTC P0157	B
DTC P0158	B
DTC P0159	B
DTC P0160	B
DTC P0161	B
DTC P0171	B
DTC P0172	B
DTC P0174	B
DTC P0175	B
DTC P0201	B
DTC P0202	B
DTC P0203	B
DTC P0204	B
DTC P0205	B
DTC P0206	B
DTC P0207	B
DTC P0208	B
DTC P0222	A
DTC P0223	A
DTC P0261	B
DTC P0262	B
DTC P0264	B
DTC P0265	B
DTC P0267	B
DTC P0268	B
DTC P0270	B
DTC P0271	B
DTC P0273	B
DTC P0274	B
DTC P0276	B
DTC P0277	B
DTC P0279	B
DTC P0280	B
DTC P0282	B
DTC P0283	B
DTC P0300	B
DTC P0301	B
DTC P0302	B
DTC P0303	B
DTC P0304	B
DTC P0305	B
DTC P0306	B
DTC P0307	B
DTC P0308	B
DTC P0315	A
DTC P0325	B
DTC P0326	B
DTC P0330	B
DTC P0331	B
DTC P0335	A
DTC P0336	B
DTC P0340	B
DTC P0341	B
DTC P0345	B
DTC P0346	B
DTC P0351	B
DTC P0352	B
DTC P0353	B
DTC P0354	B
DTC P0355	B
DTC P0356	B
DTC P0357	B
DTC P0358	B
DTC P0365	B
DTC P0366	B
DTC P0390	B
DTC P0391	B
DTC P0420	B
DTC P0430	B
DTC P0442	B
DTC P0443	B
DTC P0446	B
DTC P0449	B
DTC P0451	B
DTC P0452	B
DTC P0453	B
DTC P0454	C
DTC P0455	B
DTC P0458	B
DTC P0459	B
DTC P0496	B
DTC P0498	B
DTC P0499	B
DTC P0506	B
DTC P0507	B
DTC P0601	A
DTC P0602	A
DTC P0604	A
DTC P0606	A
DTC P0607	A
DTC P0628	C
DTC P0629	C
DTC P0638	A
DTC P0641	A
DTC P0650	A
DTC P0651	A
DTC P0686	C
DTC P0687	C
DTC P0689	C
DTC P0690	C
DTC P0700	A
DTC P1101	A
DTC P1111	C
DTC P1112	C
DTC P1114	C
DTC P1115	C
DTC P1137	B
DTC P1138	B
DTC P1157	B
DTC P1158	B
DTC P1380	C
DTC P1381	C
DTC P167A	A
DTC P167B	A
DTC P2088	B
DTC P2089	B
DTC P2090	B
DTC P2091	B
DTC P2092	B
DTC P2093	B
DTC P2094	B
DTC P2095	B
DTC P2096	B
DTC P2097	B
DTC P2098	B
DTC P2099	B
DTC P2100	A
DTC P2101	A
DTC P2108	A
DTC P2119	A
DTC P2122	A
DTC P2123	A
DTC P2127	A
DTC P2128	A
DTC P2135	A
DTC P2138	A
DTC P2176	A
DTC P2231	B
DTC P2234	B
DTC P2237	B
DTC P2240	B
DTC P2243	B
DTC P2247	B
DTC P2251	B
DTC P2254	B
DTC P2300	B
DTC P2301	B
DTC P2303	B
DTC P2304	B
DTC P2306	B
DTC P2307	B
DTC P2309	B
DTC P2310	B
DTC P2312	B
DTC P2313	B
DTC P2315	B
DTC P2316	B
DTC P2318	B
DTC P2319	B
DTC P2321	B
DTC P2322	B
DTC P2626	C
DTC P2629	B
DTC P2636	C

Diagnostic Trouble Code (DTC) Type(s)

Scheme 60

Scheme 60: Evaporative Emissions (EVAP) Hose Routing Diagram

Callout	Component Name
1	EVAP Canister Purge Solenoid Valve
2	EVAP Canister
3	Fuel Fill Neck/Fill Cap
4	Rollover Valve/Fuel Tank Pressure (FTP) Sensor
5	Fuel Tank
6	EVAP Canister Vent Solenoid Valve
7	Vent Hose/Pipe
8	EVAP Vapor Pipe
9	EVAP Purge Pipe
10	EVAP Service Port

Scheme 61

Scheme 61: Fuel Hose/Pipes Routing Diagram

Callout	Component Name
1	Jet Pump and Fuel Sender Assembly
2	Fuel Pump and Fuel Sender Assembly
3	Fuel Feed Hose
4	Fuel Feed Pipe
5	Fuel Rail and Injectors
6	Fuel Pressure Test Connection
7	Fuel Filter
8	Fuel Return Hose
9	Fuel Filler Tube
10	Fuel Tank Pressure (FTP) Sensor
11	Fuel Level Vent Valve (FLVV)
12	Fuel Tank

Engine Controls Schematic Icons

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

Scheme 62

Scheme 62: Engine Controls Schematic Icons

Scheme 63

Scheme 64

Scheme 64: Engine Controls Schematics

Scheme 65

Scheme 66

Scheme 67

Scheme 68

Scheme 69

Scheme 70

Scheme 71

Scheme 72

Scheme 73

Scheme 74

Scheme 75

Scheme 76

Scheme 76: Engine Controls Component Views

Callout	Component Name
1	Valve Cover
2	Engine Coolant Temperature (ECT) Sensor
3	Engine Oil Level Switch
4	Oil Filter
5	Engine Oil Pressure (EOP) Sensor

Scheme 77

Callout	Component Name
1	Intake Manifold
2	Fuel Injector 7
3	Fuel Injector 5
4	Fuel Injector 3
5	Evaporative Emission (EVAP) Canister Purge Solenoid Valve
6	Throttle Body
7	Throttle Actuator Control (TAC) Motor
8	Manifold Absolute Pressure (MAP) Sensor
9	Fuel Injector 2
10	Fuel Injector 4
11	Fuel Injector 8

Scheme 78

Callout	Component Name
1	Camshaft Position (CMP) Actuator Solenoid Bank 1 Exhaust
2	Camshaft Position (CMP) Sensor Bank 1 Exhaust
3	Camshaft Position (CMP) Sensor Bank 1 Intake
4	Camshaft Position (CMP) Actuator Solenoid Bank 1 Intake
5	Manifold Absolute Pressure (MAP) Sensor
6	C140
7	Ignition Coil/Module 1
8	Fuel Injector 1
9	Ignition Coil/Module 3
10	Fuel Injector 3
11	Ignition Coil/Module 5
12	Fuel Injector 5
13	Ignition Coil/Module 7
14	Fuel Injector 7
15	Fuel Injector 6
16	Starter
17	C102
18	Fuel Injector 8
19	C139
20	Ignition Coil/Module 8
21	Ignition Coil/Module 6
22	Ignition Coil/Module 4
23	Fuel Injector 4
24	Ignition Coil/Module 2
25	Fuel Injector 2
26	Camshaft Position (CMP) Actuator Solenoid Bank 2 Exhaust
27	Camshaft Position (CMP) Sensor Bank 2 Exhaust
28	Camshaft Position (CMP) Sensor Bank 2 Intake
29	Camshaft Position (CMP) Actuator Solenoid Bank 2 Intake
30	Evaporative Emission (EVAP) Canister Purge Valve

Scheme 79

Callout	Component Name
1	Knock Sensor Bank 2
2	Knock Sensor Bank 2 Connector
3	Knock Sensor Bank 1 Connector
4	Knock Sensor Bank 1
5	Crankshaft Position Sensor

Scheme 80

Callout	Component Name
1	LF Frame Rail
2	Engine Control Module (ECM)
3	A/C Refrigerant Pressure Sensor

Scheme 81

Callout	Component Name
1	MAF/IAT Sensor
2	LF Strut Tower
3	Air Filter Box

Scheme 82

Callout	Component Name
1	Park Brake Switch
2	Brake Pedal Position Sensor
3	Accelerator Pedal Position (APP) Sensor
4	Left Front Floor Panel

Scheme 83

Callout	Component Name
1	HO2S - Bank 2 Sensor 1
2	HO2S - Bank 1 Sensor 1
3	HO2S - Bank 1 Sensor 2
4	HO2S - Bank 2 Sensor 2

Scheme 84

Callout	Component Name
1	C102
2	Engine Coolant Temperature (ECT) Sensor

Callout	Component Name
1	LF Frame Rail
2	Engine Control Module (ECM)
3	A/C Refrigerant Pressure Sensor

Scheme 85

Callout	Component Name
1	EVAP Canister
2	Evaporative Emissions (EVAP) Canister Vent Solenoid (LY7/LH2)
3	Fuel Tank
4	Secondary Fuel Sender Assembly
5	Fuel Pump and Sender Assembly (LY7/LH2)
6	C420
7	Fuel Tank Pressure (FTP) Sensor (LY7/LH2)

Engine Control Module (ECM) Connector End Views

ECM Connector C1 Connector End Connector Part Information 15418483 56-Way F Micro-Pack 64 Series (BU) Pin Wire Color Circuit No. Function 1 TN/BK 2500 High Speed GMLAN Serial Data Bus (+) 2 TN 2501 High Speed GMLAN Serial Data Bus (-) 3-4 - - Not Used 5 TN 1274 5-Volt Reference 6 - - Not Used 7 WH/BK 1164 5-Volt Reference 8-9 - - Not Used 10 WH 1310 EVAP Canister Vent Solenoid Control 11 OG/BK 380 A/C Refrigerant Pressure Sensor Signal 12 - - Not Used 13 WH 17 Stop Lamp Switch Signal 14 YE 447 Starter Relay Coil Control 15-16 - - Not Used 17 PK/BK 5290 Ignition 1 Voltage 18 PK 239 Ignition 1 Voltage 19 PK 239 Ignition 1 Voltage 20 RD/WH 1440 Battery Positive Voltage 21 L-BU 1162 APP Sensor 2 Signal 22 - - Not Used 23 D-GN/WH 465 Fuel Pump Relay Control - Primary 24 BN/WH 419 MIL Control 25 D-GN/WH 459 A/C Compressor Clutch Relay Control 26 - - Not Used 27 D-BU 1161 APP Sensor 1 Signal 28 BN 818 Vehicle Speed Signal 29 YE 492 MAF Sensor Signal 30 - - Not Used 31 TN 2760 Intake Air Temperature Sensor Low Reference 32 BK/WH 2751 Signal Ground 33 OG/WH 812 12-Volt Reference 34 - - Not Used 35 GY 2700 5-Volt Reference 36 BN 1271 Low Reference 37 PU 1272 Low Reference 38-41 - - Not Used 42 D-BU 473 High Speed Cooling Fan Relay Control 43 BN 5069 Main Relay Control 44-45 - - Not Used 46 YE/BK 5728 ECM/TCM Serial Data Wake Up 47-50 - - Not Used 51 TN 472 IAT Sensor Signal 52-54 - - Not Used 55 D-GN 335 Low Speed Cooling Fan Relay Control 56 - - Not Used

ECM Connector C2 Connector End Connector Part Information 15418475 73-Way F 108-A (BK) Pin Wire Color Circuit No. Function 1-2 - - Not Used 3 D-GN 485 TP Sensor 1 Signal 4 PU 486 TP Sensor 2 Signal 5-7 - - Not Used 8 L-GN 432 MAP Sensor Signal 9 - - Not Used 10 YE 573 Crankshaft Position Sensor Signal (1) 11 L-BU 1876 Knock Sensor Signal (2) 12 GY 23 Generator Field Duty Cycle Signal 13 GY 1716 Knock Sensor Low Reference (1) 14 L-GN 5282 Camshaft Phaser Exhaust Solenoid (1) 15-16 - - Not Used 17 TN 1744 Fuel Injector 1 Control 18 L-GN/BK 1745 Fuel Injector 2 Control 19 D-BU 496 Knock Sensor 1 Signal 20 PK/BK 1746 Fuel Injector 3 Control 21 OG/BK 877 Fuel Injector 7 Control 22 TN/WH 845 Fuel Injector 5 Control 23 YE/BK 846 Fuel Injector 6 Control 24 D-BU/WH 878 Fuel Injector 8 Control 25 D-GN 5273 Camshaft Position Exhaust Sensor (1) 26 - - Not Used 27 BN/WH 5303 Camshaft Position Intake Sensor Low Reference (2) 28 GY 2303 Knock Sensor Low Reference (2) 29 PU 5284 Camshaft Phaser Intake Solenoid (1) 30 L-BU/BK 844 Fuel Injector Control (4) 31 OG/BK 5272 Camshaft Phaser Intake Solenoid (2) 32 OG 5275 Camshaft Position Intake Sensor (1) 33 D-BU 5300 Camshaft Position Intake Sensor Supply Voltage (1) 34 WH/BK 5283 Camshaft Phaser Exhaust Solenoid (2) 35 TN 5301 Camshaft Position Intake Sensor Low Reference (1) 36 OG/BK 469 Low Reference 37 TN 2752 Low Reference 38 TN 2761 Low Reference 39 BN/WH 2130 Low Reference 40 L-BU 5302 Camshaft Position Intake Sensor Supply Voltage (2) 41 PU 574 Low Reference 42 BN 2129 Low Reference 43 PU 5274 Camshaft Position Exhaust Sensor (2) 44 BN 582 TAC Motor Control - 2 45 GY 5296 Camshaft Position Exhaust Sensor Low Reference (1) 46 L-GN 5298 Camshaft Position Exhaust Sensor Supply Voltage (2) 47 BN 5299 Camshaft Position Exhaust Sensor Low Reference (2) 48 YE 581 TAC Motor Control - 1 49 YE 5276 Camshaft Position Intake Sensor (2) 50 L-GN 1867 12-Volt Reference 51 GY 2701 5-Volt Reference 52-53 - - Not Used 54 YE 410 ECT Sensor Signal 55 D-GN/WH 428 EVAP Canister Purge Solenoid Control 56-57 - - Not Used 58 PU 2121 IC 1 Control 59 OG/WH 2122 IC 2 Control 60 OG 2127 IC 7 Control 61 L-BU 2123 IC 3 Control 62 D-GN/WH 2124 IC 4 Control 63 PU/WH 2128 IC 8 Control 64 D-GN 2125 IC 5 Control 65 GY 2704 5-Volt Reference 66-67 - - Not used 68 OG 225 Generator Turn On Signal 69 L-BU/WH 2126 IC 6 Control 70 - - Not Used 71 YE/BK 5297 Camshaft Position Exhaust Sensor Supply Voltage (1) 72 - - Not Used 73 BK/WH 1551 Ground

ECM Connector C3 Connector End Connector Part Information 15418484 56-Way F 105-B (GY) Pin Wire Color Circuit No. Function 1 PU/WH 3110 Heated Oxygen Sensor High Signal Bank 1 Sensor (1) 2 TN/WH 3111 Heated Oxygen Sensor Low Signal Bank 1 Sensor (1) 3 PU/WH 5281 Heated Oxygen Sensor Pump Current Bank 2 Sensor (1) 4-11 - - Not Used 12 D-BU 1936 Primary Fuel Level Sensor Signal 13 GY/WH 3122 Heated Oxygen Sensor Heater Low Control Bank 1 Sensor (2) 14-15 - - Not Used 16 OG/WH 3223 Heated Oxygen Sensor Heater Low Control Bank 2 Sensor (2) 17 - - Not Used 18 OG/BK 1786 Transmission Park/Neutral Signal (1) 19 TN/WH 3121 Heated Oxygen Sensor Low Signal Bank 1 Sensor (2) 20 PU 3220 Heated Oxygen Sensor High Signal Bank 2 Sensor (2) 21 TN 3221 Heated Oxygen Sensor Low Signal Bank 2 Sensor (2) 22 OG 5280 Heated Oxygen Sensor Input Pump Current Bank 2 Sensor (1) 23 BN 1174 Oil Level Switch Signal 24 L-BU 1937 Secondary Fuel Level Sensor Signal 25 TN/WH 331 Oil Pressure Sensor Signal 26-36 - - Not Used 37 TN 2759 Fuel Tank Pressure Sensor Low Reference 38 BK 2755 Oil Pressure Sensor Low Reference 39 - - Not Used 40 GY/WH 3113 Heated Oxygen Sensor Heater Low Control Bank 1 Sensor (1) 41 L-GN 3212 Heated Oxygen Sensor Heater Low Control Bank 2 Sensor (1) 42 GY 2709 5-Volt Reference (LH1/LH2) 43 PU 3120 Heated Oxygen Sensor High Signal Bank 1 Sensor (2) 44 D-GN 890 Fuel Tank Pressure Sensor Signal 45 PU/WH 3210 Heated Oxygen Sensor High Signal Bank 2 Sensor (1) 46 TN/WH 3211 Heated Oxygen Sensor Low Signal Bank 2 Sensor (1) 47 - - Not Used 48 WH 5279 Heated Oxygen Sensor Pump Current Bank 1 Sensor (1) 49 L-GN 5278 Heated Oxygen Sensor Input Pump Current Bank 1 Sensor (1) 50 - - Not Used 51 GY 2705 Oil Pressure Sensor 5-Volt Reference 52-56 - - Not Used

Engine Controls Connector End Views

Accelerator Pedal Position Sensor Connector End Connector Part Information 15326829 6-Way F 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 End Connector Part Information 15326801 2-Way F GT 150 Series (BK) Pin Wire Color Circuit No. Function A BK/WH 1551 Ground B L-GN 5282 Camshaft Position (CMP) Actuator Solenoid - Exhaust Bank 1

Camshaft Position (CMP) Actuator Solenoid Exhaust - Bank 2 Connector End Connector Part Information 15326801 2-Way F GT 150 Series (BK) Pin Wire Color Circuit No. Function A BK/WH 1551 Ground B WH/BK 5283 Camshaft Position (CMP) Actuator Solenoid - Exhaust Bank 2

Camshaft Position (CMP) Actuator Solenoid Intake - Bank 1 Connector End Connector Part Information 15326801 2-Way F GT 150 Series (BK) Pin Wire Color Circuit No. Function A BK/WH 1551 Ground B PU 5284 Camshaft Position (CMP) Actuator Solenoid - Intake Bank 1

Camshaft Position (CMP) Actuator Solenoid Intake - Bank 2 Connector End Connector Part Information 15326801 2-Way F GT 150 Series (BK) Pin Wire Color Circuit No. Function A BK/WH 1551 Ground B OR/BK 5272 Camshaft Position (CMP) Actuator Solenoid - Intake Bank 2

Camshaft Position (CMP) Sensor Exhaust Bank 1 Connector End Connector Part Information 1928403870 3-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1 D-GN 5273 Camshaft Position Exhaust Sensor 2 GY 5296 Camshaft Position Exhaust Sensor Low Reference 3 YE/BK 5297 Camshaft Position Exhaust Sensor Supply Voltage

Camshaft Position (CMP) Sensor Exhaust Bank 2 Connector End Connector Part Information 1928403870 3-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1 PU 5274 Camshaft Position Exhaust Sensor 2 BN 5299 Camshaft Position Exhaust Sensor Low Reference 3 L-GN 5298 Camshaft Position Exhaust Sensor Supply Voltage

Camshaft Position (CMP) Sensor Intake Bank 1 Connector End Connector Part Information 1928403870 3-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1 OG 5275 Camshaft Position Intake Sensor 2 TN 5301 Camshaft Position Intake Sensor Low Reference 3 D-BU 5300 Camshaft Position Intake Sensor Supply Voltage

Camshaft Position (CMP) Sensor Intake Bank 2 Connector End Connector Part Information 1928403870 3-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1 YE 5276 Camshaft Position Intake Sensor 2 BN/WH 5303 Camshaft Position Intake Sensor Low Reference 3 L-BU 5302 Camshaft Position Intake Sensor Supply Voltage

Crankshaft Position (CKP) Sensor Connector End Connector Part Information 54200308 3-Way F (BK) Pin Wire Color Circuit No. Function 1 L-GN 1867 12-Volt Reference 2 YE 573 CKP Sensor (1) Signal 3 PU 574 Low Reference

Engine Coolant Temperature (ECT) Sensor Connector End Connector Part Information 12162195 2-Way F Metri-Pack 150.2 Series Sealed, Pull To Seat (BK) Pin Wire Color Circuit No. Function A YE 410 ECT Sensor Signal B TN 2761 Low Reference

Engine Oil Pressure (EOP) Sensor Connector End Connector Part Information 15336121 3-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A BK 2755 Low Reference B TN/WH 331 Oil Pressure Sensor Signal C GY 2705 5-Volt Reference A

Evaporative Emission (EVAP) Canister Purge Solenoid Valve Connector End Connector Part Information 12124037 2-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 5290 Ignition 1 Voltage B D-GN/WH 428 EVAP Canister Purge Solenoid Control

Evaporative Emission (EVAP) Canister Vent Solenoid Connector End Connector Part Information 12052643 2-Way F Metri-Pack 150 Series Sealed (RD) Pin Wire Color Circuit No. Function A OG 1540 Battery Positive Voltage B WH 1310 EVAP Canister Vent Solenoid Control

Fuel Injector 1 Connector End Connector Part Information 7283-6430-30 2-Way F Yazaki 1.5 Series (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5291 Ignition 1 Voltage 2 TN 1744 Fuel Injector 1 Control

Fuel Injector 2 Connector End Connector Part Information 7283-6430-30 2-Way F Yazaki 1.5 Series (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5292 Ignition 1 Voltage 2 L-GN/BK 1745 Fuel Injector 2 Control

Fuel Injector 3 Connector End Connector Part Information 7283-6430-30 2-Way F Yazaki 1.5 Series (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5291 Ignition 1 Voltage 2 PK/BK 1746 Fuel Injector 3 Control

Fuel Injector 4 Connector End Connector Part Information 7283-6430-30 2-Way F Yazaki 1.5 Series (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5292 Ignition 1 Voltage 2 L-BU/BK 844 Fuel Injector 4 Control

Fuel Injector 5 Connector End Connector Part Information 7283-6430-30 2-Way F Yazaki 1.5 Series (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5291 Ignition 1 Voltage 2 TN/WH 845 Fuel Injector 5 Control

Fuel Injector 6 Connector End Connector Part Information 7283-6430-30 2-Way F Yazaki 1.5 Series (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5292 Ignition 1 Voltage 2 YE/BK 846 Fuel Injector 6 Control

Fuel Injector 7 Connector End Connector Part Information 7283-6430-30 2-Way F Yazaki 1.5 Series (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5291 Ignition 1 Voltage 2 OG/BK 877 Fuel Injector 7 Control

Fuel Injector 8 Connector End Connector Part Information 7283-6430-30 2-Way F Yazaki 1.5 Series (BK) Pin Wire Color Circuit No. Function 1 PK/BK 5292 Ignition 1 Voltage 2 D-BU/WH 878 Fuel Injector 8 Control

Fuel Pump and Sender Assembly Connector End Connector Part Information 12160482 4-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A D-BU 1936 Fuel Level Sensor Signal B GY 120 Fuel Pump Supply Voltage C BK 1050 Ground D BK 2759 Fuel Tank Pressure Sensor Low Reference

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

Heated Oxygen Sensor (HO2S) - Bank 1 Sensor 1 Connector End Connector Part Information 01475104-1 6-Way F Amp (BK) Pin Wire Color Circuit No. Function 1 PU/WH 3110 HO2S Reference Voltage Bank 1 Sensor 1 2 PU/WH 5281 HO2S Output Pump Current Bank 1 Sensor 1 3 PK/BK 5293 Engine Main Relay Fused Control (4) 4 GY/WH 3113 HO2S Heater Low Control Bank 1 Sensor 1 5 TN/WH 3111 HO2S Low Reference Bank 1 Sensor 1 6 OG 5280 HO2S Input Pump Current Bank 1 Sensor 1

Heated Oxygen Sensor (HO2S) - Bank 1 Sensor 2 Connector End Connector Part Information 12160825 4-Way M Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A TN/WH 3121 HO2S Low Signal Bank 1 Sensor 2 B PU 3120 HO2S High Signal Bank 1 Sensor 2 C GY/WH 3122 HO2S Heater Low Control Bank 2 Sensor 1 D PK/BK 5294 Engine Main Relay Fused Control (5)

Heated Oxygen Sensor (HO2S) - Bank 2 Sensor 1 Connector End Connector Part Information 01475104-1 6-Way F Amp (BK) Pin Wire Color Circuit No. Function 1 PU/WH 3210 Heated Oxygen Sensor High Signal Bank 2 Sensor 2 WH 5279 Heated Oxygen Sensor Pump Current Bank 1 Sensor 3 PK/BK 5293 Engine Main Relay Fused Control 4 L-GN 3212 Heated Oxygen Sensor Heater Low Control Bank 2 Sensor 5 TN/WH 3211 Heated Oxygen Sensor Low Signal Bank 2 Sensor 6 L-GN 5278 Heated Oxygen Sensor Input Pump Current Bank 1 Sensor

Heated Oxygen Sensor (HO2S) - Bank 2 Sensor 2 Connector End Connector Part Information 12160825 4-Way M Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A TN 3221 Heated Oxygen Sensor Low Signal Bank 2 Sensor B PU 3220 Heated Oxygen Sensor High Signal Bank 2 Sensor C OG/WH 3223 Heated Oxygen Sensor Heater Low Control Bank 2 Sensor D PK/BK 5294 Engine Main Relay Fused Control

Ignition Coil/Module 1 Connector End Connector Part Information 15354716 4-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 5291 Ignition 1 Voltage B PU 2121 IC 1 Control C BN 2129 Low Reference D BK/WH 1451 Ground

Ignition Coil/Module 2 Connector End Connector Part Information 15354716 4-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 5292 Ignition 1 Voltage B OG/WH 2122 IC 2 Control C BN/WH 2130 Low Reference D BK/WH 1451 Ground

Ignition Coil/Module 3 Connector End Connector Part Information 15354716 4-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 5291 Ignition 1 Voltage B L-BU 2123 IC 3 Control C BN 2129 Low Reference D BK/WH 1451 Ground

Ignition Coil/Module 4 Connector End Connector Part Information 15354716 4-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 5292 Ignition 1 Voltage B D-GN/WH 2124 IC 4 Control C BN/WH 2130 Low Reference D BK/WH 1451 Ground

Ignition Coil/Module 5 Connector End Connector Part Information 15354716 4-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 5291 Ignition 1 Voltage B D-GN 2125 IC 5 Control C BN 2129 Low Reference D BK/WH 1451 Ground

Ignition Coil/Module 6 Connector End Connector Part Information 15354716 4-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 5292 Ignition 1 Voltage B L-BU/WH 2126 IC 6 Control C BN/WH 2130 Low Reference D BK/WH 1451 Ground

Ignition Coil/Module 7 Connector End Connector Part Information 15354716 4-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 5291 Ignition 1 Voltage B OG 2127 IC 7 Control C BN 2129 Low Reference D BK/WH 1451 Ground

Ignition Coil/Module 8 Connector End Connector Part Information 15354716 4-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK/BK 5292 Ignition 1 Voltage B PU/WH 2128 IC 8 Control C BN/WH 2130 Low Reference D BK/WH 1451 Ground

Knock Sensor (KS) Bank 1 Connector End Connector Part Information 15374222 2-Way F GT 150 Series Sealed (WH) Pin Wire Color Circuit No. Function A D-BU 496 Knock Sensor Signal (1) B GY 1716 Knock Sensor Low Reference (1)

Knock Sensor (KS) Bank 2 Connector End Connector Part Information 15374222 2-Way F GT 150 Series Sealed (WH) Pin Wire Color Circuit No. Function A L-BU 1876 Knock Sensor Signal (2) B GY 2303 Knock Sensor Low Reference (2)

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

MAF/IAT Sensor Connector End Connector Part Information 1928403112 4-Way F Bosch (BK) Pin Wire Color Circuit No. Function 1 TN 472 IAT Sensor Signal 2 TN 2760 Low Reference 3 YE 492 MAF Sensor Signal 4 OG/WH 812 12-Volt Reference or I/P Dimming Voltage Reference

Secondary Fuel Sender Assembly Connector End Connector Part Information OEM: 12160482 Service: 12167154 4-Way F Metri-Pack 150 Series Sealed (WH) Terminal Part Information Terminal: Terminal Seal: Release Tool: Core Crimp: Insulation Crimp: Test Probe: Pin Wire Color Circuit No. Function A L-BU 1937 Secondary Fuel Level Sensor Signal B-C - - Not Used D BK 2759 Fuel Tank Pressure Sensor Low Reference

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

Removal Procedure

Note. Turn the ignition OFF when installing or removing the PCM connectors and disconnecting or reconnecting the power to the PCM (battery cable, PCM pigtail, PCM fuse, jumper cables, etc.) in order to prevent internal PCM damage.

Using a scan tool, retrieve the percentage of remaining engine oil and the remaining automatic transmission fluid life. Record the remaining engine oil and the remaining automatic transmission fluid life.
Turn OFF the ignition.
Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/cadillac/sts/i-2004-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
Remove the front air deflector. Refer to «Air Deflector Replacement - Front»(/cadillac/sts/i-2004-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
Disconnect the engine control module (ECM) electrical connectors (1).
Remove the ECM mounting nuts (2).
Remove the ECM from the vehicle.

Installation Procedure

Install the ECM to the vehicle.
Install the ECM mounting nuts (2). Tighten: Tighten the nuts to 8 N.m (71 lb in).
Connect the ECM electrical connectors (1).
Install the front air deflector. Refer to «Air Deflector Replacement - Front»(/cadillac/sts/i-2004-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
Lower the vehicle.
Connect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/cadillac/sts/i-2004-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
Program the ECM. Refer to «Engine Control Module Programming and Setup (4.6L)»(/cadillac/sts/i-2004-2007/remont/communication-devices/#programming-and-setup-all-systems__engine-control-module-programming-and-setup) or «Engine Control Module Programming and Setup (3.6L - LY7)»(/cadillac/sts/i-2004-2007/remont/communication-devices/#programming-and-setup-all-systems__engine-control-module-programming-and-setup) in Programming and Setup.

CKP System Variation Learn Procedure

Install a scan tool.
Monitor the engine control module (ECM) for DTCs with a scan tool. If other DTCs are set, except DTC P0315, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/sts/i-2004-2007/remont/oem-general-information/#vehicle-dtc-information__diagnostic-trouble-code-dtc-list) in Vehicle DTC Information for the applicable DTC.
Select the crankshaft position variation learn procedure with a scan tool.
The scan tool instructs you to perform the following: Accelerate to wide open throttle (WOT). Release throttle when fuel cut-off occurs. Observe fuel cut-off for applicable engine. Engine should not accelerate beyond calibrated RPM value. Release throttle immediately if value is exceeded. Block drive wheels. Set parking brake. DO NOT apply brake pedal. Cycle ignition from OFF to ON. Apply and hold brake pedal. Start and idle engine. Turn A/C OFF. Vehicle must remain in Park or Neutral. The scan tool monitors certain component signals to determine if all the conditions are met to continue with the procedure. The scan tool only displays the condition that inhibits the procedure. The scan tool monitors the following components: Crankshaft position (CKP) sensors activity - If there is a CKP sensor condition, refer to the applicable DTC. Camshaft position (CMP) signal activity - If there is a CMP signal condition, refer to the applicable DTC. Engine coolant temperature (ECT) - If the engine coolant temperature is not warm enough, idle the engine until the engine coolant temperature reaches the correct temperature.
Enable the CKP system variation learn procedure with the scan tool and perform the following: IMPORTANT: While the learn procedure is in progress, release the throttle immediately when the engine starts to decelerate. The engine control is returned to the operator and the engine responds to throttle position after the learn procedure is complete. Accelerate to WOT. Release throttle when fuel cut-off occurs.
The scan tool displays Learn Status: Learned this ignition. If the scan tool indicates that DTC P0315 ran and passed, the CKP variation learn procedure is complete. If the scan tool indicates DTC P0315 failed or did not run, refer to «DTC P0315»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-dtc-p0134-to-dtc-p0390) . If any other DTCs set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/sts/i-2004-2007/remont/oem-general-information/#vehicle-dtc-information__diagnostic-trouble-code-dtc-list) in Vehicle DTC Information for the applicable DTC.
Turn OFF the ignition for 30 seconds after the learn procedure is completed successfully.

The CKP system variation learn procedure is also required when the following service procedures have been performed, regardless of whether or not DTC P0315 is set

An engine replacement
A ECM replacement
A harmonic balancer replacement
A crankshaft replacement
A CKP sensor replacement
Any engine repairs which disturb the crankshaft to CKP sensor relationship.

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

Turn OFF the ignition
Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Drain the coolant to below the level of the engine coolant temperature (ECT) sensor. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.
Disconnect the ECT sensor harness connector.
Remove the ECT sensor.

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

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

Coat the sensor threads with sealer GM P/N 1050805, or equivalent.
Install the ECT sensor. Tighten: Tighten the ECT sensor to 20 N.m (15 lb ft).
Connect the ECT sensor harness connector.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Refill the coolant system. Refer to «Draining and Filling Cooling System»(/cadillac/sts/i-2004-2007/remont/cooling-system-mechanical/#engine-cooling-system) in Engine Cooling.

Disconnect the mass air flow (MAF)/intake air temperature (IAT) sensor electrical connector.
Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Remove the MAF/IAT sensor screws.
Carefully remove the MAF/IAT sensor from the air cleaner housing cover.
Discard the MAF/IAT sensor gasket.

Install a NEW MAF/IAT sensor gasket.
Carefully install the MAF/IAT sensor into the air cleaner housing cover.
Install the MAF/IAT sensor screws. Tighten: Tighten the screws to 4 N.m (35 lb in).
Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Reconnect the MAF/IAT sensor electrical connector.

Turn the ignition OFF.
Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the manifold absolute pressure (MAP) sensor electrical connector.
Remove the bolt (1) and bracket (2) from the MAP sensor (3).
Remove the MAP sensor (3).
Inspect the MAP sensor seal for wear or damage. If a problem is found, replace as necessary.

Install the MAP sensor (3).
Install the bracket (2) and bolt (1). Tighten: Tighten the bracket bolt to 12 N.m (106 lb in).
Connect the MAP sensor electrical connector.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Note. Refer to Oxygen Sensor Notice in Cautions and Notices.

IMPORTANT

Bank 1 on the LH2 engine in this vehicle is the right side of the engine while sitting in the drivers seat. Sensor 1 is the sensor closest to the engine, or farthest forward towards the front of vehicle. A special anti-seize compound is used on the oxygen sensor threads. New service sensors should already have the compound applied to the threads. Coat the threads of a reused sensor with anti-seize compound P/N 5613695 or equivalent.

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the oxygen sensor electrical connector from the engine wiring harness connector at the rear of the right head.
Note the wire routing and attachment points for reassembly.
Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
Remove oxygen sensor from the exhaust manifold.

Install the oxygen sensor in the exhaust manifold. Tighten: Tighten the heated oxygen sensor (HO2S) to 42 N.m (31 lb ft).
Lower the vehicle.
Route and attach the wiring as noted in disassembly.
Connect the oxygen sensor electrical connector to the engine wiring harness connector at the rear of the right head.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Note. Refer to Oxygen Sensor Notice in Cautions and Notices.

IMPORTANT

Bank 1 on the LH2 engine in this vehicle is the right side of the engine while sitting in the drivers seat. Sensor 2 is the second sensor down stream from the engine towards the rear of the vehicle. A special anti-seize compound is used on the oxygen sensor threads. New service sensors should already have the compound applied to the threads. Coat the threads of a reused sensor with anti-seize compound P/N 5613695 or equivalent.

Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
Disconnect the oxygen sensor electrical connector.
Note the wire routing and attachment points for reassembly.
Remove the oxygen sensor from the exhaust pipe.

Install the oxygen sensor to the exhaust pipe. Tighten: Tighten the HO2S sensor to 42 N.m (31 lb ft).
Route and attach the wiring as noted during disassembly.
Connect the oxygen sensor electrical connector.
Lower the vehicle.

Note. Refer to Oxygen Sensor Notice in Cautions and Notices.

IMPORTANT

Bank 2 on the LH2 engine in this vehicle is the left side of the engine while sitting in the drivers seat. Sensor 1 is the sensor closest to the engine, or farthest towards the front of vehicle. A special anti-seize compound is used on the oxygen sensor threads. New service sensors should already have the compound applied to the threads. Coat the threads of a reused sensor with anti-seize compound P/N 5613695 or equivalent.

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the oxygen sensor electrical connector from the engine wiring harness at the rear of the left head.
Note the wire routing and attachment points for reassembly.
Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
Remove the oxygen sensor from the exhaust manifold.

Install the heated oxygen sensor (HO2S) to the exhaust manifold. Tighten: Tighten the HO2S to 42 N.m (31 lb ft).
Lower the vehicle.
Route and attach the wiring as noted during disassembly.
Connect the oxygen sensor electrical connector to the engine wiring harness connector at the rear of the left head.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Note. Refer to Oxygen Sensor Notice in Cautions and Notices.

IMPORTANT

Bank 2 on the LH2 engine in this vehicle is the left side of the engine while sitting in the drivers seat. Sensor 2 is the second sensor down stream from the engine towards the rear of the vehicle. A special anti-seize compound is used on the oxygen sensor threads. New service sensors should already have the compound applied to the threads. Coat the threads of a reused sensor with anti-seize compound P/N 5613695 or equivalent.

Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
Disconnect the oxygen sensor electrical connector.
Note the wire routing and attachment points for reassembly.
Remove the oxygen sensor from the exhaust pipe.

Install the oxygen sensor to the exhaust pipe. Tighten: Tighten the front heated oxygen sensor (HO2S) to 42 N.m (31 lb ft).
Route and attach the wiring as noted during disassembly.
Connect the oxygen sensor electrical connector.
Lower the vehicle.

Remove the closeout/insulator panel from under the dashboard on the drivers side. Refer to «Closeout/Insulator Panel Replacement - Left»(/cadillac/sts/i-2004-2007/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-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 9 N.m (80 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»(/cadillac/sts/i-2004-2007/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Disconnect the electrical connector from the throttle body assembly.
Remove the throttle body assemble mounting bolts.
Remove the throttle body and throttle body gasket from the water housing.
Discard the throttle body gasket.

Note. Do not use a cleaner which contains methyl ethyl ketone. This extremely strong solvent may damage components and is not necessary for this type of cleaning. Use a carburetor cleaner in order to remove deposits. Refer to the instructions provided with the cleaner.

IMPORTANT

Do not reuse the old throttle body gasket.

Install the NEW gasket to the throttle body assembly.
Install the throttle body assembly to the water housing.
Install the throttle body assembly mounting bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
Connect the electrical connector to the throttle body assembly.
Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Throttle Body Service

IMPORTANT

Over an extended period of time and mileage, deposits may accumulate on the back of the throttle plate. Typically these deposits pose no problems. Occasionally the deposits may accumulate to a point where throttle valve movement is effected. This procedure should not be performed on vehicles with mileage under 80 450 km (50,000 mi).

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Inspect the throttle body bore and the throttle body plate for deposits. You will need to open the throttle plate in order to inspect all surfaces.
Clean the throttle body bore and the throttle plate using a clean shop towel with GM top engine cleaner, P/N 1052626 or AC Delco Carburetor Tune-up Conditioner, P/N X66P, or equivalent product.
Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Tools Required

J 34730-1A Fuel Pressure Gage

CAUTION

Gasoline or gasoline vapors are highly flammable. A fire could occur if an ignition source is present. Never drain or store gasoline or diesel fuel in an open container, due to the possibility of fire or explosion. Have a dry chemical (Class B) fire extinguisher nearby.

CAUTION

Relieve the fuel system pressure before servicing fuel system components in order to reduce the risk of fire and personal injury. After relieving the system pressure, a small amount of fuel may be released when servicing the fuel lines or connections. In order to reduce the chance of personal injury, cover the regulator and the fuel line fittings with a shop towel before disconnecting. This will catch any fuel that may leak out. Place the towel in an approved container when the disconnection is complete.

Turn the ignition OFF.
Disconnect the negative battery cable in order to avoid possible fuel discharge if an accidental attempt is made to start the engine. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/cadillac/sts/i-2004-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Connect the J 34730-1A to the fuel pressure valve. Wrap a shop towel around the fitting while connecting the gage in order to avoid spillage.
Install the bleed hose into an approved container.
Open the valve in order to bleed the system pressure. Fuel connections are now safe for servicing.
Drain any fuel remaining in the gage into an approved container.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/cadillac/sts/i-2004-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.

J 34730-1A Fuel Pressure Gage

CAUTION

Refer to Gasoline/Gasoline Vapors Caution in Cautions and Notices.

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

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Install the J 34730-1A to the fuel pressure service connection, located on the fuel rail.
Turn ON the ignition, with the engine OFF.
Place the bleed hose of the fuel pressure gage into an approved gasoline container.
Open the bleed valve on the fuel pressure gage in order to bleed the air from the fuel pressure gage.
Command the fuel pump ON with a scan tool.
Close the bleed valve on the fuel pressure gage.
Command the fuel pump ON with a scan tool.
Inspect for fuel leaks.

Place the fuel pressure gage bleed hose into an approved container and open the bleed valve in order to bleed OFF fuel system pressure.
Place a shop towel under the J 34730-1A to catch any remaining fuel spillage.
Remove the J 34730-1A from the fuel pressure connection.
Drain any fuel remaining in the fuel pressure gage into an approved container.
Inspect for leaks using the following procedure: Turn ON the ignition, with the engine OFF for 2 seconds. Turn OFF the ignition, for 10 seconds. Turn ON the ignition, with the engine OFF. Inspect for fuel leaks.
Install the cap on the fuel pressure connection.
Install the fuel injection sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Quick Connect Fitting(s) Service (Metal Collar)

Tools Required

J 37088-A Fuel Line Disconnect Tool Set
J 44581 Fuel Line Disconnect Tool. See «Special Tools»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__special-tools) .

Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Remove the retainer from the quick-connect fitting.
Blow dirt out of the fitting using compressed air.
Choose the correct tool for the size and access of the fitting: J 37088-A or J 44581 . See «Special Tools»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__special-tools) . Insert the tool into the female connector, then push inward to release the locking tabs.
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 fitting together to cause the retaining tabs to snap into place.
Once installed, pull on both sides of the fitting to make sure the connection is secure.
Install the retainer to the quick-connect fitting.

Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Blow dirt out of the fitting using compressed air.
Squeeze the plastic tabs of the male end connector.
Pull the connection apart.
Wipe off the male pipe end using a clean shop towel.
Inspect both ends of the fitting for dirt and burrs.
Clean or replace the components as required.

CAUTION

In order to reduce the risk of fire and personal injury, before connecting fuel pipe fittings, always apply a few drops of clean engine oil to the male pipe ends. This will ensure proper reconnection and prevent a possible fuel leak. During normal operation, the O-rings located in the female connector will swell and may prevent proper reconnection if not lubricated.

Apply a few drops of clean engine oil to the male pipe end.
Push both sides of the quick-connect fitting together in order to cause the retaining tabs/fingers to snap into place.
Pull on both sides of the quick connect fitting in order to make sure the connection is secure.

Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
Disconnect the quick-connect fittings (3 and 4) at the fuel filter inlet. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__quick-connect-fittings-service-metal-collar) or «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Disconnect the threaded fitting (1) at the fuel filter outlet.
Drain any remaining fuel into an approved gasoline container.
Remove the fuel filter (2).
Remove the fuel pipe O-ring.
Discard the fuel filter into an approved container.

Remove the protective caps from the new fuel filter.
If originally equipped, install new plastic connector retainers on the fuel filter inlets. Install the new retainers in the same position as on the old fuel filter.
Lubricate the new fuel pipe O-ring with clean engine oil.
Install the fuel pipe O-ring.
Slide the fuel filter into place.
Connect the quick-connect fittings (3 and 4) to the inlet side of the filter. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__quick-connect-fittings-service-metal-collar) or «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Connect the threaded fitting to the fuel filter outlet. Use a back-up wrench in order to prevent the fuel filter from turning. Tighten: Tighten the fuel filter outlet fitting to 30 N.m (22 lb ft).
Lower the vehicle.
Ensure that the fuel tank filler cap is installed correctly.
Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/cadillac/sts/i-2004-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
Perform the following procedure in order to inspect for leaks: Turn ON the ignition, with the engine OFF for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition, with the engine OFF. Inspect for fuel leaks.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

J 36850 Transjel Lubricant
J 42960-2 Fuel Flapper Door Holder
J 45004 Fuel Drain Hose

CAUTION

Refer to Gasoline/Gasoline Vapors Caution in Cautions and Notices.

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.

Remove the fuel filler cap.
Install the J 42960-2 into the fuel fill pipe in order to hold the door open.
Insert the J 45004 into the fuel tank until the hose reaches the bottom of the fuel tank.
Use an air operated pump device in order to drain the fuel into an approved gasoline container. Up to 26 liters (7 gallons) of residual fuel may remain in the secondary side of the fuel tank.
Simultaneously twist and pull in order to remove the J 45004 from the fuel tank.

CAUTION

Refer to Gasoline/Gasoline Vapors Caution in Cautions and Notices.

Drain the fuel tank. Refer to «Fuel Tank Draining Procedure»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction__fuel-tank-draining-procedure) .
Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Remove the exhaust system. Refer to «Exhaust System Replacement»(/cadillac/sts/i-2004-2007/remont/exhaust/#engine-exhaust-system__exhaust-system-replacement) in Engine Exhaust.
Remove the propeller shaft. Refer to «Propeller Shaft Replacement - Rear (AWD)»(/cadillac/sts/i-2004-2007/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-rear-awd) or «Propeller Shaft Replacement - Rear (RWD)»(/cadillac/sts/i-2004-2007/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-rear-rwd) in Propeller Shaft.
Disconnect the filler hose (1) from the fuel tank.
Disconnect the filler vent tube (2) from the evaporative emission (EVAP) hose. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__quick-connect-fittings-service-metal-collar) or «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) in order to disconnect the following from the chassis bundle: The fuel feed hoses (3 and 4) The fuel EVAP hose
Disconnect the fuel tank electrical connector.
Disconnect the EVAP hoses from the EVAP canister.
Pull outward on the retainer tab in order to disengage the retainer from the chassis.
Disconnect the electrical connector from the EVAP canister.
Raise the lower control arms using a suitable screw jack (3) in order to remove the load from the lower shock bolts (2).
Remove the lower shock bolts (2).
Remove the screw jack (3).
Position the screw jack under the rear frame near the adjuster tie bar, in order to support the front of the rear frame.
Remove the 2 front bolts from the rear frame.
Lower the screw jack until there is approximately 50 mm (2 in) (a) between the front mounting surface of the rear frame and the chassis. This will allow clearance to access the fuel tank strap bolts.
Remove the fuel tank strap bolts.
Position the fuel tank straps downward around the rear frame.
Carefully bend the fuel tank straps ONLY enough to allow the fuel tank to be removed.
With the aid of an assistant, carefully lower the fuel tank from the vehicle.
Remove the following components if replacing just the fuel tank: The primary fuel tank module - Refer to «Fuel Tank Module Replacement - Primary»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) . The secondary fuel tank module - Refer to «Fuel Tank Module Replacement - Secondary»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) . The fuel tank pressure sensor - Refer to «Fuel Tank Pressure Sensor Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction) .

Install the following components if fuel tank replacement was necessary: The primary fuel tank module - Refer to «Fuel Tank Module Replacement - Primary»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) . The secondary fuel tank module - Refer to «Fuel Tank Module Replacement - Secondary»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) . The fuel tank pressure sensor - Refer to «Fuel Tank Pressure Sensor Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction) .
With the aid of an assistant, carefully raise the fuel tank to the vehicle, aligning the filler neck with the filler hose.
Carefully bend the fuel tank straps back to their original form.
Position the fuel tank straps around the rear frame and upward into position, aligning the holes in the straps with the threaded holes in the chassis.
Install the fuel tank strap bolts. Tighten: Tighten the fuel tank strap bolts to 50 N.m (37 lb ft).
Connect the filler hose (1) to the fuel tank. Tighten: Tighten the fuel filler tube hose clamp (3) to 3.5 N.m (31 lb in).
Connect the filler vent tube (2) to the EVAP hose. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Connect the EVAP hoses to the EVAP canister.
Insert the retainer into the chassis and press inward on the tab to engage.
Connect the electrical connector to the EVAP canister.
Connect the fuel tank electrical connector.
Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) or «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__quick-connect-fittings-service-metal-collar) in order to connect the following to the chassis bundle: The fuel feed hoses (3 and 4) The fuel EVAP hose
Raise the rear frame using the screw jack.
Install the 2 front bolts to the rear frame. Tighten: Tighten the rear frame bolts to 265 N.m (195 lb ft).
Remove the screw jack.
Position the screw jack (3) under the lower control arm in order to raise the lower control arms (2).
Install the lower shock bolts (2). Tighten: Tighten the lower shock bolts to 150 N.m (111 lb ft).
Remove the screw jack (3).
Install the propeller shaft. Refer to «Propeller Shaft Replacement - Rear (AWD)»(/cadillac/sts/i-2004-2007/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-rear-awd) or «Propeller Shaft Replacement - Rear (RWD)»(/cadillac/sts/i-2004-2007/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-rear-rwd) in Propeller Shaft.
Install the exhaust system. Refer to «Exhaust System Replacement»(/cadillac/sts/i-2004-2007/remont/exhaust/#engine-exhaust-system__exhaust-system-replacement) in Engine Exhaust.
Refill the fuel tank.
Inspect for fuel leaks.

Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) .
Disconnect the fuel tank pressure sensor electrical connector (1).
Remove the fuel tank pressure sensor from the evaporative emission (EVAP) canister.

Install the fuel tank pressure sensor to the EVAP canister until fully seated.
Connect the fuel tank pressure sensor electrical connector (1).
Lower the vehicle.

Remove the fuel filler cap.
Drain the fuel tank below the level of the fuel filler hose. Refer to «Fuel Tank Draining Procedure»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction__fuel-tank-draining-procedure) .
Remove the bolts securing the fuel filler tube to the body.
Remove the right rear wheel. Refer to «Tire and Wheel Removal and Installation»(/cadillac/sts/i-2004-2007/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
Remove the right rear wheelhouse liner. Refer to «Wheelhouse Liner Panel Replacement - Rear»(/cadillac/sts/i-2004-2007/remont/exterior-body-panels/#body-rear-end) in Body Rear End.
Remove the fuel filler tube brace bolt.
Disconnect the fuel filler hose (1) from the fuel tank.
Disconnect the filler vent tube (2) from the evaporative emission (EVAP) hose. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Remove the fuel filler tube from the vehicle.

Position the fuel filler tube to the vehicle.
Connect the filler hose (1) to the fuel tank. Tighten: Tighten the fuel filler tube hose clamp (3) to 3.5 N.m (31 lb in).
Connect the filler vent tube (2) to the EVAP hose. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Install the fuel filler tube brace bolt. Tighten: Tighten the fuel filler tube brace bolt to 9 N.m (80 lb in).
Install the bolts securing the fuel filler tube to the body. Tighten: Tighten the fuel filler tube bolts to 3.5 N.m (31 lb in).
Install the right rear wheelhouse liner. Refer to «Wheelhouse Liner Panel Replacement - Rear»(/cadillac/sts/i-2004-2007/remont/exterior-body-panels/#body-rear-end) in Body Rear End.
Install the right rear wheel. Refer to «Tire and Wheel Removal and Installation»(/cadillac/sts/i-2004-2007/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
Add fuel to the fuel tank.
Inspect for fuel leaks.
Install the fuel filler cap.

J 45747 Fuel Tank Sender Wrench

Remove the fuel tank hoses. Refer to «Fuel Hoses/Pipes Replacement - Filter to Tank»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Disconnect the electrical connector from the primary fuel tank module.
Rotate the cam lock ring counter-clockwise using the J 45747 .
Remove the cam lock ring from the fuel tank.
Carefully lift the primary fuel tank module (1) from the fuel tank only enough to access the transfer tube (2).
Complete the following in order to disconnect the transfer tube from the primary fuel tank module: Pull the locking mechanism away from the module. Remove the transfer tube from the module.
Remove the primary fuel tank module from the fuel tank.
Remove the primary fuel tank module seal from the module. Do not reuse the seal.

Place the new primary fuel tank module seal (1) over the module (2).
Complete the following in order to connect the transfer tube (2) to the primary fuel tank module (1). Grasp the transfer tube (2) from inside the fuel tank. Position the module (1) near the module opening. Connect the transfer tube (2) to the module (1).
Carefully insert the primary fuel tank module (1) into the fuel tank.
Press the primary fuel tank module (1) downward, aligning the module to the encapsulated ring.
Position the cam lock ring to the fuel tank.
Rotate the cam lock ring clockwise using the J 45747 until fully seated.
Connect the electrical connector to the primary fuel tank module.
Install the fuel tank hoses. Refer to «Fuel Hoses/Pipes Replacement - Filter to Tank»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .

J 45747 Fuel Tank Sender Wrench

Remove the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Disconnect the electrical connector from the secondary fuel tank module.
Rotate the cam lock ring counter-clockwise using the J 45747 .
Remove the cam lock ring from the fuel tank.
Carefully lift the secondary fuel tank module (2) from the fuel tank only enough to access the transfer tube (1).
Complete the following in order to disconnect the transfer tube from the secondary fuel tank module. Pull the locking mechanism away from the module. Remove the transfer tube from the module.
Remove the secondary fuel tank module from the fuel tank.
Remove the secondary fuel tank module seal from the module. Do not reuse the seal.

Place the new secondary fuel tank module seal (1) over the module (2).
Complete the following in order to connect the transfer tube (1) to the secondary fuel tank module (2). Grasp the transfer tube (1) from inside the fuel tank. Position the module (2) near the module opening. Connect the transfer tube (1) to the module (2).
Carefully insert the secondary fuel tank module (2) into the fuel tank.
Press the secondary fuel tank module (2) downward, aligning the module to the encapsulated ring.
Position the cam lock ring to the fuel tank.
Rotate the cam lock ring clockwise using the J 45747 until fully seated.
Connect the electrical connector to the secondary fuel tank module.
Install the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .

CAUTION

Refer to Gasoline/Gasoline Vapors Caution in Cautions and Notices.

Remove the primary fuel tank module. Refer to «Fuel Tank Module Replacement - Primary»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Disconnect the fuel level sensor electrical connector (1) from the module.
Complete the following in order to remove the fuel level sensor (1) from the module assembly: Pull the locking tab (2) away from the sensor (1). Slide the sensor (1) away from the module assembly.

Complete the following in order to install the fuel level sensor (1) to the module assembly: Align the tabs of the sensor (1) with the slots in the module assembly. Slide the sensor (1) fully into position, ensure the locking tab (2) is engaged.
Connect the fuel level sensor electrical connector (1) to the module.
Install the primary fuel tank module. Refer to «Fuel Tank Module Replacement - Primary»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .

Remove the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Disconnect the following from the primary fuel tank module: The pressure hose The return hose
Disconnect the hoses from the retaining feature at the fuel tank.

Clean any contamination from the male pipe ends of the primary fuel tank module.
Connect the hoses to the retaining feature at the fuel tank.
Connect the following to the primary fuel tank module: The pressure hose The return hose
Install the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .

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

Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Disconnect the feed hose/pipe (1) from the fuel rail. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__quick-connect-fittings-service-metal-collar) .
Plug the open ports to prevent fuel loss and contamination.
Disconnect the evaporative emission (EVAP) quick connect fitting (2). Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Open the retainers (1 and 2) located at the rear of the engine and on the front of dash.
Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) and «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__quick-connect-fittings-service-metal-collar) in order to disconnect the following quick connect fittings from the chassis bundle: The fuel filter (2) The fuel hose The fuel EVAP hose Plug the open outlet ports to prevent fuel loss and contamination.
Pull the locking mechanism (1) outward in order to disengage the fuel/brake bundle chassis pipe retainers from the rail.
Open the retainers (1) located at the forward portion of the rail in order to remove the chassis hose/pipes.
Complete the following in order to remove the chassis hose/pipes from the retainers (2) located at the rearward portion of the rail: Pull the retainers (2) free from the rail. Open the retainers (2) at the top. Remove the chassis hose/pipes from the retainers (2).
Pull downward in order to disconnect the fuel/brake bundle chassis pipe retainer from the underbody.
Remove the bolt securing the fuel filter bracket to the body.
Remove the bolts securing the transmission support to the underbody, from the right side only.
Pull the right side transmission support down only enough to allow removal of the chassis fuel hose/pipes.
Partially lower the hoist only enough to simultaneously gain access to both the front and rear portions of the chassis fuel hose/pipes.
With the aid of an assistant, carefully guide the chassis fuel hose/pipes down through the engine compartment, removing from the bottom.

Clean any of the contamination from the male line ends and apply a few drops of clean engine oil.
With the aid of an assistant, carefully guide the chassis fuel hose/pipes up through the engine compartment into position.
Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
Pull the right side transmission support down only enough to allow installation of the chassis fuel hose/pipes.
Install the bolts securing the transmission support to the underbody. Tighten: Tighten the transmission support bolts to 60 N.m (44 lb ft).
Install the bolt securing the fuel filter bracket to the body. Tighten: Tighten the fuel filter bracket bolt to 9 N.m (80 lb in).
Push upward in order to connect the fuel/brake bundle chassis pipe retainer to the underbody.
Complete the following in order to install the chassis hose/pipes to the retainers (2) located at the rearward portion of the rail: Install the chassis hose/pipes into the retainers (2). Close the retainers (2) at the top. Insert the retainers (2) into the rail.
Install the chassis hose/pipes into the retainers (1) located at the forward portion of the rail.
Close the retainers.
Push the locking mechanism (1) inward in order to engage the fuel/brake bundle chassis pipe retainers to the rail.
Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) and «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__quick-connect-fittings-service-metal-collar) in order to connect the following quick connect fittings to the chassis bundle: The fuel filter (2) The fuel hose The fuel EVAP hose
Lower the vehicle.
Insert the chassis hose/pipes into the retainers (1 and 2) located at the rear of the engine and the front of dash.
Close the retainers.
Connect the EVAP quick connect fitting (2). Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Connect the fuel feed pipe (1) to the fuel rail. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__quick-connect-fittings-service-metal-collar) .
Check the fuel system for leaks.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Fuel System Cleaning

CAUTION

Refer to Gasoline/Gasoline Vapors Caution in Cautions and Notices.

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

Remove the in-line fuel filter. Refer to «Fuel Filter Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Inspect the fuel system for contamination of the in-line fuel filter. Replace the filter after cleaning the fuel lines if the filter is plugged or contaminated.
Remove the fuel module assemblies. Refer to «Fuel Tank Module Replacement - Primary»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) and «Fuel Tank Module Replacement - Secondary»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Locate the tank in a suitable work area away from any heat, any flame, or any other source of ignition.
Perform the following procedures: Inspect the fuel sender strainer. Replace the primary fuel tank module if the strainer is contaminated. Inspect the secondary fuel tank module for debris. Clean the secondary fuel tank module if debris is found. CAUTION: Wear safety glasses when using compressed air, as flying dirt particles may cause eye injury. Use compressed air in order to apply air pressure to the transfer tube.
Flush the fuel tank with running hot water for at least five minutes. Pour the water out of the fuel sender assembly opening. Rock the tank in order to ensure that the removal of the water from the tank is complete.
Disconnect the fuel feed hose/pipe from the fuel rail. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__quick-connect-fittings-service-metal-collar) .
Use compressed air in order to apply air pressure to the fuel lines in the opposite direction from the normal fuel flow.
Remove the fuel injectors and fuel rail. Refer to «Fuel Injectors and Fuel Rail Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Clean and inspect the fuel injectors and fuel rail.

Assemble the fuel system as follows

Install the fuel injectors and fuel rail. Refer to «Fuel Injectors and Fuel Rail Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Install the fuel module assemblies. Refer to «Fuel Tank Module Replacement - Primary»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) and «Fuel Tank Module Replacement - Secondary»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Install the fuel filter. Refer to «Fuel Filter Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Connect the fuel line to the fuel rail. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__quick-connect-fittings-service-metal-collar) .

Relieve the fuel system pressure. Refer to «Fuel Pressure Relief Procedure»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Remove the cross vehicle brace. Refer to «Brace Replacement - Cross Vehicle»(/cadillac/sts/i-2004-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
Clean the fuel rail assembly with a spray type engine cleaner, GM X-30A or equivalent, if necessary. Follow the package instructions. Do not soak the fuel rail in liquid cleaning solvent.
Disconnect the fuel feed hose/pipe (1) from the fuel rail. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__quick-connect-fittings-service-metal-collar) .
Remove the positive crankcase ventilation (PCV) dirty air hose.
Disconnect the evaporative emission (EVAP) quick connect fitting (2). Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Open the retainers (1 and 2) located at the right side rear of the engine and the front of dash. Position the lines aside.
Disconnect the left side fuel injector wiring harness connectors (1) from the fuel injectors (2).
Disconnect the right side fuel injector wiring harness connectors (1) from the fuel injectors (2).
Remove the fuel injector sight shield bracket.
Remove the fuel rail attaching studs.
Remove the fuel rail assembly.
Remove the injector lower O-ring seal from the spray tip end of each injector.
Discard the O-ring seals.
Remove the retainers from the fuel injectors.
Remove the fuel injectors from the fuel rail.
Remove the O-ring seals from the fuel injectors. Discard the O-ring seals.

Lubricate the new fuel injector O-ring seals with clean engine oil.
Install the new fuel injector O-ring seals on to the fuel injectors.
Install the fuel injectors to the fuel rail using new retainer clips.
Ensure that the injectors are aligned by orientating the electrical connectors perpendicular to the crankshaft centerline.
Lubricate and install the new O-ring seals on the spray tip end of each injector.
Align the fuel injectors and fuel rail to the intake manifold.
Carefully press the fuel rail assembly downward until fully seated against the intake manifold.
Install the fuel rail attaching studs. Tighten: Tighten the studs to 10 N.m (89 lb in).
Install the fuel injector sight shield bracket nuts. Tighten: Tighten the nuts to 10 N.m (89 lb in).
Connect the right side fuel injector electrical connectors (1) to each fuel injector (2).
Connect the left side fuel injector electrical connectors (1) to each fuel injector (2).
Install the fuel feed and EVAP lines to the retaining clips (1 and 2) at the right side rear of the engine and at the front of dash.
Install the EVAP quick connect fitting (2) to the purge valve. Refer to «Quick Connect Fitting(s) Service (Plastic Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Install the positive crankcase ventilation (PCV) dirty air hose.
Connect the fuel feed hose/pipe to the fuel rail (1). Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__quick-connect-fittings-service-metal-collar) .
Install the cross vehicle brace. Refer to «Brace Replacement - Cross Vehicle»(/cadillac/sts/i-2004-2007/remont/exterior-body-panels/#body-front-end) in Body Front End.
Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/cadillac/sts/i-2004-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
Inspect for fuel leaks using the following procedure: Turn ON the ignition, with the engine OFF for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition, with the engine OFF. Inspect for fuel leaks.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical.

Loosen the fuel cap in order to relieve the system pressure.
Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the evaporative emission (EVAP) canister purge valve electrical connector (1).
Disconnect the EVAP purge pipe (2) from the EVAP canister purge valve.
Remove the EVAP canister purge valve retaining bolt.
Remove the EVAP canister purge valve from the water housing.

Lubricate the O-ring with clean engine oil.
Install the EVAP canister purge valve to the water housing.
Install the EVAP canister purge valve retaining bolt. Tighten: Tighten the bolt to 12 N.m (106 lb in).
Connect the EVAP purge pipe (2) to the EVAP canister purge valve.
Connect the EVAP canister purge valve electrical connector (1).
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Remove the evaporative emission (EVAP) canister. Refer to «Evaporative Emission (EVAP) Canister Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction) .
Clean away any debris that may be present around the EVAP canister vent valve.
Twist the EVAP canister vent valve counter-clockwise.
Pull the EVAP canister vent valve from the EVAP canister.

Insert the EVAP canister vent valve into the EVAP canister.
Twist the EVAP canister vent valve clockwise into the locked position.
Install the EVAP canister. Refer to «Evaporative Emission (EVAP) Canister Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction) .

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

Remove the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Remove the chassis to canister evaporative emission (EVAP) hose from the following: The body retainer (1) The 3 retaining features (2) on the fuel tank The retainer clip (3)
Remove the EVAP hose from the fuel tank.

Position the EVAP hose to the fuel tank.
Install the chassis to canister evaporative emission (EVAP) hose to the following: The body retainer (1) The 3 retaining features (2) on the fuel tank The retainer clip (3)
Install the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .

Remove the rear frame. Refer to «Frame Replacement - Rear»(/cadillac/sts/i-2004-2007/remont/frames-subframes-crossmembers/#frame-underbody) in Frame and Underbody.
Disconnect the evaporative emission (EVAP) hoses from the EVAP canister.
Disconnect the electrical connector from the EVAP canister.
Remove the EVAP canister retaining nuts.
Complete the following in order to remove the EVAP canister: Lower the rear of the canister enough to clear the 2 weld studs. Slide the canister rearward from the body brace.

Complete the following in order to install the EVAP canister: Insert the fresh air tube and tab on the canister forward into the body brace. Rotate the rear of the canister up over the 2 weld studs on the floor pan.
Install the EVAP canister retaining nuts. Tighten: Tighten the EVAP canister retaining nuts to 6 N.m (53 lb in).
Connect the EVAP hoses to the EVAP canister.
Connect the electrical connector to the EVAP canister.
Install the rear frame. Refer to «Frame Replacement - Rear»(/cadillac/sts/i-2004-2007/remont/frames-subframes-crossmembers/#frame-underbody) in Frame and Underbody.

Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2004-2007/remont/hoistjack/#general-information) in General Information.
Using a 90 degree pick, disengage the lower filter cover clips.
Insert a flat-bladed tool between the filter cover and canister, and push up to disengage the upper clips.
Remove and discard the evaporative emission (EVAP) canister filter cover.
Remove and discard the EVAP canister filter.
Clean the inside of the EVAP canister filter housing with a clean shop towel.

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

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Remove the ignition coil cover from the cam cover by lifting straight up.
Disconnect the ignition coil wiring harness electrical connector from the coil that needs to be replaced.
Remove the ignition coil retaining bolt.
Carefully remove the ignition coil.

Install the ignition coil.
Install the ignition coil retaining bolt. Tighten: Tighten the ignition coil retaining bolt to 10 N.m (89 lb in).
Reconnect the ignition coil electrical connector.
Install the ignition coil cover to the cam cover.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Remove the ignition coil cover from the cam cover by lifting straight up.
Disconnect the ignition coil wiring harness electrical connector from the coil that needs to be replaced.
Remove the ignition coil retaining bolt.
Carefully remove the ignition coil assembly.

Install the ignition coil.
Install the ignition coil retaining bolt. Tighten: Tighten the ignition coil retaining bolt to 10 N.m (89 lb in).
Reconnect the ignition coil electrical connector.
Install the ignition coil cover to the cam cover.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Remove the ignition coil cover from the cam cover by lifting straight up.
Disconnect the ignition module assembly wiring harness electrical connector.
Remove the ignition module assembly retaining bolts and studs.
Carefully, remove the ignition module assembly.

Install the ignition module assembly.
Install the ignition module retaining bolts and studs. Tighten: Tighten the ignition module retaining bolts and studs to 10 N.m (89 lb in).
Reconnect the ignition module electrical connector.
Install the ignition coil cover to the cam cover.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Remove the ignition coil cover from the cam cover by lifting straight up.
Disconnect the ignition module assembly wiring harness electrical connector.
Remove the ignition module assembly retaining bolts and studs.
Carefully, remove the ignition module assembly.

Install the ignition module assembly.
Install the ignition module retaining bolts. Tighten: Tighten the ignition module retaining bolts and studs to 10 N.m (89 lb in).
Reconnect the ignition module electrical connector.
Install the ignition coil cover to the cam cover.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Spark Plug Operation

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

Power loss
Poor fuel economy
Loss of speed
Hard starting
Poor engine performance

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

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

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

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

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

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

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

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

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

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

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

Remove the ignition control modules. Refer to «Ignition Control Module Replacement - Bank 1»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) and «Ignition Control Module Replacement - Bank 2»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Clean the spark plug recess area with low pressure air.
Remove the spark plugs from the cylinder heads.
Inspect the spark plugs. Refer to «Spark Plug Inspection»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .

Measure the spark plug gap on the spark plugs to be installed. Compare the measurement to the gap specifications. Refer to «Ignition System Specifications»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__ignition-system-specifications) , correct as necessary.
Install the spark plugs to the cylinder heads. Tighten: Tighten the spark plugs to 20 N.m (15 lb ft).
Install the ignition control modules. Refer to «Ignition Control Module Replacement - Bank 1»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) and «Ignition Control Module Replacement - Bank 2»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .

Remove the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the crankshaft position sensor electrical connector.
Remove the crankshaft sensor retaining bolt.
Remove the crankshaft sensor.

Lubricate the crankshaft sensor O-ring with clean engine oil.
Install the crankshaft sensor and the retaining bolt. Tighten: Tighten the retaining bolt to 10 N.m (89 lb in).
Connect the crankshaft position sensor electrical connector.
Install the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Perform the «CKP System Variation Learn Procedure»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction__ckp-system-variation-learn-procedure) .

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the electrical connector from the left bank exhaust camshaft position sensor (2).
Remove the camshaft sensor retaining bolt.
Remove the left bank exhaust camshaft sensor (4).

Lubricate the camshaft sensor O-ring with engine oil.
Install the left bank exhaust camshaft position sensor (4) and retaining bolt. Tighten: Tighten the retaining bolt to 10 N.m (89 lb in).
Reconnect the camshaft sensor electrical connector (2).
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Operate the engine and inspect the camshaft sensor for engine oil leaks.

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the electrical connector from the left bank intake camshaft position sensor (1).
Remove the camshaft sensor retaining bolt.
Remove the left bank intake camshaft sensor (3).

Lubricate the camshaft sensor O-ring with engine oil.
Install the left bank intake camshaft position sensor (3) and retaining bolt. Tighten: Tighten the retaining bolt to 10 N.m (89 lb in).
Reconnect the camshaft sensor electrical connector (1).
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Operate the engine and inspect the camshaft sensor for engine oil leaks.

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the electrical connector from the right bank exhaust camshaft position sensor (2).
Remove the camshaft sensor retaining bolt.
Remove the right bank exhaust camshaft sensor (1).

Lubricate the camshaft sensor O-ring with engine oil.
Install the right bank exhaust camshaft position sensor (1) and retaining bolt. Tighten: Tighten the retaining bolt to 10 N.m (89 lb in).
Reconnect the camshaft sensor electrical connector (2).
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Operate the engine and inspect the camshaft sensor for engine oil leaks.

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the electrical connector from the right bank intake camshaft position sensor (1).
Remove the camshaft sensor retaining bolt.
Remove the right bank intake camshaft sensor (2).

Lubricate the camshaft sensor O-ring with engine oil.
Install the right bank intake camshaft position sensor (2) and retaining bolt. Tighten: Tighten the retaining bolt to 10 N.m (89 lb in).
Reconnect the camshaft sensor electrical connector (1).
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Operate the engine and inspect the camshaft sensor for engine oil leaks.

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the actuator solenoid electrical connector.
Remove the right intake camshaft position (CMP) actuator solenoid bolts.
Remove the right intake CMP actuator solenoid.

IMPORTANT

The CMP actuator solenoid must be precisely aligned to the CMP actuator oil control valve on the end of the camshaft. This is accomplished with an alignment pin. Failure to align the CMP actuator solenoid to the CMP actuator oil control valve can lead to poor engine performance and engine component damage.

To allow for CMP actuator solenoid to CMP actuator oil control valve alignment, DO NOT install the NEW CMP actuator solenoid alignment plugs at this time.

Camshaft Position Actuator Solenoid Alignment Procedure

Make an alignment pin from drill rod 15/64 inch diameter and at least 50 mm (1.97 in) long.
Verify that the alignment pin will pass through the CMP actuator solenoid alignment hole.
Verify that the alignment pin will fit into the alignment hole in the CMP actuator oil control valve.
Apply a 2 mm (0.079 in) bead of RTV GM P/N 12378521 (Canadian P/N 88901148) around the flange of the CMP actuator solenoid.
Install the CMP actuator solenoid over the oil control valve.
Install the alignment pin through the solenoid alignment hole and into the oil control valve alignment hole.
With the alignment pin in place, install the CMP actuator solenoid bolts. Tighten: Tighten the CMP actuator solenoid bolts to 8 N.m (71 lb in).
Remove the alignment pin.
Install a NEW CMP actuator solenoid plug.
Connect the electrical connector to the actuator solenoid.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the actuator solenoid electrical connector.
Remove the right exhaust camshaft position (CMP) actuator solenoid bolts.
Remove the right exhaust CMP actuator solenoid.

IMPORTANT

To allow for CMP actuator solenoid to CMP actuator oil control valve alignment, DO NOT install the NEW CMP actuator solenoid alignment plugs at this time.

Make an alignment pin from drill rod 15/64 inch diameter and at least 50 mm (1.97 in) long.
Verify that the alignment pin will pass through the CMP actuator solenoid alignment hole.
Verify that the alignment pin will fit into the alignment hole in the CMP actuator oil control valve.
Apply a 2 mm (0.079 in) bead of RTV GM P/N 12378521 (Canadian P/N 88901148) around the flange of the CMP actuator solenoid.
Install the CMP actuator solenoid over the oil control valve.
Install the alignment pin through the solenoid alignment hole and into the oil control valve alignment hole.
With the alignment pin in place, install the CMP actuator solenoid bolts. Tighten: Tighten the CMP actuator solenoid bolts to 8 N.m (71 lb in).
Remove the alignment pin.
Install a NEW CMP actuator solenoid plug.
Connect the electrical connector to the actuator solenoid.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Remove the remote power steering reservoir. Refer to «Remote Power Steering Fluid Reservoir Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/manual-power-steering/#power-steering-system) or «Remote Power Steering Fluid Reservoir Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.
Disconnect the actuator solenoid electrical connector.
Remove the left intake camshaft position (CMP) actuator solenoid bolts.
Remove the left intake CMP actuator solenoid.

IMPORTANT

To allow for CMP actuator solenoid to CMP actuator oil control valve alignment, DO NOT install the NEW camshaft position actuator solenoid alignment plugs at this time.

Make an alignment pin from drill rod 15/64 inch diameter and at least 50 mm (1.97 in) long.
Verify that the alignment pin will pass through the CMP actuator solenoid alignment hole.
Verify that the alignment pin will fit into the alignment hole in the CMP actuator oil control valve.
Apply a 2 mm (0.079 in) bead of RTV GM P/N 12378521 (Canadian P/N 88901148) around the flange of the CMP actuator solenoid.
Install the CMP actuator solenoid over the oil control valve.
Install the alignment pin through the solenoid alignment hole and into the oil control valve alignment hole.
With the alignment pin in place, install the CMP actuator solenoid bolts. Tighten: Tighten the CMP actuator solenoid bolts to 8 N.m (71 lb in).
Remove the alignment pin.
Install a NEW CMP actuator solenoid plug.
Connect the electrical connector to the actuator solenoid.
Install the remote power steering reservoir. Refer to «Remote Power Steering Fluid Reservoir Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/manual-power-steering/#power-steering-system) or «Remote Power Steering Fluid Reservoir Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.

Remove the remote power steering reservoir. Refer to «Remote Power Steering Fluid Reservoir Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/manual-power-steering/#power-steering-system) or «Remote Power Steering Fluid Reservoir Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.
Disconnect the actuator solenoid electrical connector.
Remove the left exhaust camshaft position (CMP) actuator solenoid bolts.
Remove the left exhaust CMP actuator solenoid.

IMPORTANT

To allow for CMP actuator solenoid to CMP actuator oil control valve alignment, DO NOT install the NEW CMP actuator solenoid alignment plugs at this time.

Make an alignment pin from drill rod 15/64 inch diameter and at least 50 mm (1.97 in) long.
Verify that the alignment pin will pass through the CMP actuator solenoid alignment hole.
Verify that the alignment pin will fit into the alignment hole in the CMP actuator oil control valve.
Apply a 2 mm (0.079 in) bead of RTV GM P/N 12378521 (Canadian P/N 88901148) around the flange of the CMP actuator solenoid.
Install the CMP actuator solenoid over the oil control valve.
Install the alignment pin through the solenoid alignment hole and into the oil control valve alignment hole.
With the alignment pin in place, install the CMP actuator solenoid bolts. Tighten: Tighten the CMP actuator solenoid bolts to 8 N.m (71 lb in).
Remove the alignment pin.
Install a NEW CMP actuator solenoid plug.
Connect the electrical connector to the actuator solenoid.
Install the air conditioning, power steering and water pump drive belt tensioner. Refer to «Drive Belt Tensioner Replacement - Air Conditioning, Power Steering and Water Pump»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Install the remote power steering reservoir. Refer to «Remote Power Steering Fluid Reservoir Replacement (LH2)»(/cadillac/sts/i-2004-2007/remont/manual-power-steering/#power-steering-system) or «Remote Power Steering Fluid Reservoir Replacement (LY7)»(/cadillac/sts/i-2004-2007/remont/manual-power-steering/#power-steering-system) in Power Steering System.

Remove the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the knock sensor (KS) electrical connector (2).
Remove the KS bolt.
Remove the KS (1).

Thoroughly clean the mating surfaces of the KS and the engine block. The entire contact surface of the KS must lie directly on the engine block.
Install the KS (1) and bolt. Tighten: Tighten bolt to 20 N.m (15 lb ft).
Ensure that the wiring harness is installed correctly.
Connect the KS electrical connector (2).
Install the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Remove the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the knock sensor (KS) electrical connector (3).
Remove the KS bolt.
Remove the KS (4).

Thoroughly clean the mating surfaces of the KS and the engine block. The entire contact surface of the KS must lie directly on the engine block.
Install the KS (4) and bolt. Tighten: Tighten the bolt to 20 N.m (15 lb ft).
Ensure that the wiring harness is installed correctly.
Connect the KS electrical connector (3).
Install the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Remove the air cleaner outlet duct from the vehicle. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Remove the air cleaner housing screws.
Open the air cleaner housing.
Remove the air cleaner element.
Remove any loose debris that may be found laying in the base of the air cleaner.

Install the new air filter element.
Close the air cleaner housing.
Install the air cleaner housing screws. Tighten: Tighten the air cleaner housing screws to 3 N.m (27 lb in).
Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .

Remove the air cleaner outlet duct from the vehicle. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Disconnect the mass air flow (MAF)/intake air temperature (IAT) sensor electrical connector.
Remove the MAF/IAT sensor if necessary. Refer to «Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Remove the coolant hose from the retaining feature on the top of the air cleaner assembly. Position the hose aside.
Remove the screws securing the air cleaner assembly to the vehicle and remove the assembly.

IMPORTANT

An improperly installed air cleaner or a distorted or missing intake air duct may cause a diagnostic trouble code (DTC) to set. Ensure that the air cleaner assembly and intake air duct is installed correctly and that there are no kinks or folds in the intake air duct. Debris in the air cleaner assembly or MAF sensor inlet screen, that may distort air flow can set a DTC.

Install the air cleaner assembly into the vehicle.
Install the air cleaner assembly screws. Tighten: Tighten the air cleaner assembly screws to 10 N.m (89 lb in).
Install the coolant hose into the retaining feature on the top of the air cleaner assembly.
Install the MAF/IAT sensor if previously removed. Refer to «Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .
Connect the MAF/IAT sensor electrical connector.
Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/cadillac/sts/i-2004-2007/remont/testing-diagnostics/#engine-control-system-46l-lh2-introduction) .

Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).
Disconnect the positive crankcase ventilation (PCV) tube from the air cleaner duct.
Loosen the air duct clamp at the throttle body.
Loosen the air duct clamp at the mass air flow (MAF)/intake air temperature (IAT) sensor.
Remove the air cleaner duct from the vehicle.

Install the air cleaner duct to the vehicle.
Tighten the air cleaner duct clamps at the throttle body and the MAF/IAT sensor. Tighten: Tighten the air duct clamps to 3 N.m (27 lb in).
Connect the PCV tube to the air cleaner duct.
Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement»(/cadillac/sts/i-2004-2007/remont/mechanical/#engine-mechanical-46l-lh2-2-of-6) in Engine Mechanical - 4.6L (LH2).

Engine Control Module (ECM) Description

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

Malfunction Indicator Lamp (MIL) Operation

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

Scheme 86

Scheme 86: Malfunction Indicator Lamp (MIL) Operation

Scheme 87

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

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

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

Throttle Actuator Control (TAC) System Description

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

Accelerator pedal position (APP) sensing
Throttle positioning to meet driver and engine demands
Throttle position sensing
Internal diagnostics
Cruise control functions
Manage TAC electrical power consumption

The TAC system components include the following

The APP sensors
The throttle body assembly
The engine control module (ECM)

Accelerator Pedal Position (APP) Sensor

The accelerator pedal position (APP) sensor is made up of 2 sensors that are housed inside one assembly. The engine control module (ECM) supplies a separate 5-volt reference and the low reference circuit for each of the sensors. The 5-volt reference for APP sensor 1 is supplied from the same source in the ECM as the 5-volt reference for the mass air flow (MAF) sensor and the fuel tank pressure (FTP) sensor. The 5-volt reference voltage for all of the sensors is supplied on separate ECM terminals, but the terminals are connected internally to a voltage supply. The APP sensor 1 sends a signal from the sensor to the ECM indicating the accelerator pedal position. The ECM actuates the throttle plates based on this information.

Throttle Position Sensors

The throttle position (TP) sensors 1 and 2 are located within the throttle body assembly. The TP sensors share a common 5-volt reference circuit and a common low reference circuit. The 5-volt reference circuit is also shared with accelerator pedal position (APP) sensor 2. The 5-volt reference voltage is supplied on 2 separate engine control module (ECM) terminals, but the terminals are connected internally to the same voltage supply. Each TP sensor has an individual signal circuit, which provides the ECM with a signal voltage proportional to throttle the plate movement. When the throttle plate is in the closed position, the TP sensor 1 signal voltage is near the low reference and increases as the throttle plate is opened. TP sensor 2 signal voltage at closed throttle is near the 5-volt reference and decreases as the throttle plate is opened.

Throttle Body Assembly

The throttle body assembly contains the following

Throttle blade
Throttle actuator motor
Throttle position (TP) sensor 1 and 2

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

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

The TP sensors are used to determine the throttle plate angle. The TP sensors provide the control module with signal voltage proportional to throttle plate movement. Both TP sensor signal voltages are low at closed throttle and increase as the throttle opens.

Engine Control Module

The engine control module (ECM) determines the driver's intent and then calculates the appropriate throttle response.

Camshaft Actuator System Description

The camshaft position (CMP) actuator system is used for a variety of engine performance enhancements. The CMP actuator system accomplishes this by controlling the amount of intake and exhaust valve overlap. These enhancements include the following

Lower emission output through exhaust gas recirculation (EGR) control
A wider engine torque range
Improved gas mileage
Improved engine idle stability

The CMP actuator system is comprised of the following components

Four CMP actuator solenoids
Four oil control valves
Four vane style CMP actuators
Four CMP sensors

The CMP actuator system requires a very complex electrical signal from the engine control module (ECM) in order to control the position of the CMP actuators. The electrical signal requires use of an un-fixed pulse width modulation (PWM) signal as well as 2 different operating frequencies of 150 and 500 Hz. Changes in the PWM can happen every 100 milliseconds and thus makes it difficult to measure the correct PWM or frequency with a DMM during CMP actuator control. At idle, the ECM commands a consistent 7 percent duty cycle at 150 Hz. The ECM uses this signal in order to sense certain circuit failures.

Scheme 88

Callout	Component Name
1	Camshaft Position (CMP) Actuator Housing Bank 1 (Right)
2	Camshaft Position (CMP) Actuator Oil Control Valves
3	Camshaft Position (CMP) Actuator Bank 1 (Right) Exhaust
4	Camshaft Position (CMP) Actuator Bank 1 (Right) Intake
5	Secondary Timing Drive Chain Bank 1 (Right)
6	Secondary Timing Drive Chain Bank 2 (Left)
7	Engine Block
8	Camshaft Position (CMP) Actuator Bank 2 (Left) Exhaust
9	Camshaft Position (CMP) Actuator Bank 2 (Left) Intake
10	Oil Outlet Tube
11	Camshaft Position (CMP) Actuator Housing Bank 2 (Left)
12	Camshaft Position (CMP) Actuator Solenoids

The CMP actuator solenoids, or electromagnets, are located on the front of the engine and are mounted to their corresponding bank CMP actuator housing.

The oil control valves are threaded, and attach the CMP actuators to the front of the camshafts. The oil control valve meters the oil flow to the CMP actuator through the advancing and retarding oil ports. With no command fro the ECM, all of the oil is ported to the advancing chambers of the exhaust CMP actuators and to the retarding chambers of the intake CMP actuators. With full command from the ECM, all of the oil is ported to the retarding chambers of the exhaust CMP actuators and to the advancing chambers of the intake CMP actuators. When the intake or exhaust camshafts reach a desired position, above 0 degrees on the scan tool, the ECM will apply an electrical signal to the solenoids in order to hold the CMP actuators in the desired position. The oil control valves will port engine oil evenly to the advancing and retarding chambers of the CMP actuators in order to hold the camshafts in the desired position. The oil control valves will allow enough engine oil to flow to compensate for any leakage past the CMP actuators in order to hold the camshafts in a steady position.

The CMP actuators interface the timing chain to the camshafts, and are able to change the camshaft timing in relation to the crankshaft. The intake CMP actuators have the ability to move the intake camshafts a total of 40 degrees from the parked position. The exhaust CMP actuators have the ability to move the exhaust camshafts a total of 50 degrees from the parked position. With the engine OFF or with the CMP actuators not commanded, the exhaust CMP actuators are parked at the full advance position of 133 degrees ATDC and the intake CMP actuators are parked at the full retard position of 117 degrees before top dead center (BTDC). The CMP Angle parameters on the scan tool will indicate 0 degrees with the engine running and the CMP actuators in the parked position for both exhaust and intake camshafts.

Camshaft	Crankshaft position when the intake or exhaust valve begins to open with camshaft actuators in park	Crankshaft position when the intake or exhaust valve begins to open with camshaft actuators at full travel
Intake Camshafts	133° ATDC (CMP actuator position is at 0° on scan tool).	93° ATDC (CMP actuator position is at 40° on scan tool)
Exhaust Camshafts	117° BTDC (CMP actuator position is at 0° on scan tool)	67° BTDC (CMP actuator position is at 50° on scan tool)

CMP Actuator Authority

A locking pin keeps the CMP actuators in the parked position in order to avoid valve train noise upon engine start-up. The locking pin will release the actuator after the engine oil pressure is sufficient to overcome the locking pin spring pressure. The exhaust CMP actuators have return springs. The return springs are necessary to assist the CMP actuators to return to the parked position due to the rotational inertia of the valve train components upon engine shutdown.

An oil outlet tube is used to transfer oil from a dedicated oil galley in the engine block, from the replaceable oil filter, up to each head and is located in the timing chain area. The oil outlet tube incorporates a non-replaceable 40 micron oil filter. If the filter becomes clogged with contamination and can not be cleaned, the tube and filter must be replaced as an assembly. Engine oil pressure, level, viscosity, and temperature can have an adverse affect on the CMP actuator performance.

The CMP sensors are used by the ECM to monitor the position of the camshafts. The intake cam sensor wheels have 8X targets. The exhaust cam sensor wheels have a 1X target. The ECM can detect a camshaft position variance as small as 2 degrees. The variance is the difference between the actual camshaft position and the desired camshaft position. A CMP actuator performance DTC will set if the ECM detects the camshaft position has a 2 degree to 11 degree variance. A 2 degree variance takes more time for the ECM to detect than an 11 degree variance. A crankshaft to camshaft correlation DTC will set if the ECM detects a 12 degree variance or more.

If a CMP actuator system DTC is present, the ECM will disable the CMP actuator system control for that ignition cycle.

CMP Actuator System Operation

The engine control module (ECM) sends an electrical signal to the camshaft position (CMP) actuator solenoids through the control circuits when a camshaft timing change is desired. The ground circuit of the CMP actuator solenoid is used as a return. The CMP actuator solenoid uses electromagnetic force to pull on the plunger of the oil control valve. The oil control valve will port the pressurized engine oil to either the advancing or retarding chambers of the CMP actuator. The CMP actuator, in turn, changes the camshaft position relative to crankshaft position. The ECM uses the CMP sensors to determine the position of the camshafts.

The ECM calculates the optimum CMP through the following inputs

Engine speed
Manifold absolute pressure (MAP)
Throttle position indicated angle
Crankshaft position (CKP)
CMP
Engine load
Barometric pressure (BARO)

The ECM monitors the following inputs before assuming control of the CMP actuator system

Engine coolant temperature (ECT)
Loop status
Calculated engine oil temperature (EOT)
Engine oil pressure (EOP)
Engine oil level
Crankshaft/camshaft correlation
Ignition 1 signal voltage
Barometric pressure (BARO)

Fuel Tank

The fuel storage tank is made of high density polyethylene. The fuel storage tank is held in place by 2 metal straps that are attached to the underbody of the vehicle. The tank shape includes a sump in order to maintain a constant supply of fuel around the fuel pump strainer during low fuel conditions or during aggressive maneuvers.

The fuel tank also contains a fuel vapor vent valve with a roll-over protection. The vent valve also features a 2-phase vent calibration which increases the fuel vapor flow to the canister when the operating temperatures increase the tank pressure beyond an established threshold.

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.

Fuel Tank Filler Pipe

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

Scheme 89

Scheme 89: Fuel Filler Cap

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.

Scheme 90

Scheme 90: Modular Fuel Sender

Callout	Component Name
1	The Fuel Pump
2	The Fuel Gauge Float Arm
3	The Fuel Reservoir

The modular fuel sender assembly mounts to the threaded opening of the plastic fuel tank with a multi-lipped seal and a threaded retainer (nut). The reservoir, containing the exterior inlet strainer, the electric fuel pump, and the pump strainer, maintains contact with the tank bottom. This design provides

Optimum fuel level in the integral fuel reservoir during all fuel tank levels and during driving conditions
An improved tank fuel level measuring accuracy
An improved coarse straining and added pump inlet filtering
More extensive internal fuel pump isolation for noiseless operation

The modular fuel sender assembly maintains an optimum fuel level in the reservoir (bucket). The fuel entering the reservoir is drawn in by the following components

The first stage of the fuel pump through the external strainer AND/OR
The secondary umbrella valve OR
The return fuel line, whenever the level of fuel is below the top of the reservoir

Fuel Pump

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

Fuel Sender Strainers

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

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.

Scheme 91

Scheme 91: In-Line Fuel Filter

The fuel filter is located on the fuel feed pipe, between the fuel pump and the fuel rail. The electric fuel pump supplies fuel through the in-line fuel filter to the fuel injection system. The fuel pressure regulator keeps the fuel available to the fuel injectors at a regulated pressure. Unused fuel is returned from the fuel filter to the fuel tank by a separate fuel return pipe. The paper filter element (2) traps particles in the fuel that may damage the fuel injection system. The filter housing (1) is made to withstand maximum fuel system pressure, exposure to fuel additives, and changes in temperature. There is no service interval for fuel filter replacement. Replace a restricted fuel filter.

EVAP Lines and Hoses

The evaporative emission (EVAP) line extends from the fuel tank vent valve to the EVAP canister and into the engine compartment. The EVAP line is made of nylon and connects to the EVAP canister with a fuel resistant rubber hose and quick connect fittings.

Scheme 92

Scheme 92: Fuel Pressure Regulator

The fuel pressure regulator attaches to the fuel return pipe on the fuel sender assembly. The fuel pressure regulator is a diaphragm-operated relief valve. A software bias compensates the injector on-time because the fuel pressure regulator is not referenced to manifold vacuum. The injector pulse width varies with the signal from the mass air flow/intake air temperature (MAF/IAT) sensor.

With the engine running at idle, the system fuel pressure at the pressure test connection should be between 380-410 kPa (55-60 psi). With the system pressurized and the pump OFF, the pressure should stabilize and hold. If the pressure regulator supplies a fuel pressure which is too low or too high, a driveability condition will result.

Fuel Rail

The fuel rail consists of 3 parts

The pipe that carries fuel to each injector
The fuel pressure test port
Eight 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.

The function of the fuel and air control system is to manage the fuel and the air delivery to each cylinder, optimizing the performance and the driveability of the engine under all driving conditions. The fuel sender allows retrieval of fuel from the tank and also provides information on the fuel level. An electric fuel pump contained in the modular fuel sender pumps the fuel through the nylon lines and an in-line fuel filter to the fuel rail. The pump is designed to provide the fuel at a pressure above the regulated pressure which is needed by the injectors. The fuel is then distributed through the fuel rail to 6 injectors inside of the intake manifold. The fuel pressure is controlled by a pressure regulator that is mounted on the fuel rail. The fuel system in this vehicle is recirculating. This means that any excess fuel that is not injected into the cylinders is sent back to the fuel tank by a separate nylon line. This removes any air and any vapors from the fuel as well as keeping the fuel cool during hot weather operation. Each fuel injector is located directly above each cylinders 2 intake valves. The throttle body regulates the air flow from the air cleaner into the intake manifold, which then distributes this air to each cylinders 2 intake valves.

Unleaded fuel must be used with all of the gasoline engines for a proper emission control system operation. Using unleaded fuel will also minimize any spark plug fouling and extend the engine oil life. Leaded fuel can damage the emission control system, and use of leaded fuel can result in loss of emission warranty coverage.

Engine Fueling

The engine is fueled by 8 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 (FT). 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 FT, and the long term FT. The battery voltage adjustment is necessary since the changes in the voltage across the injector affect the injector flow rate.

Fuel Trim

The engine control module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. The ECM monitors the heated oxygen sensor (HO2S) signal voltage while fuel injectors based on this signal. The ideal fuel trim (FT) values are around 0 percent for both short term and long term FT. A positive FT value indicates the ECM is adding fuel in order to compensate for a lean condition by increasing the pulse width. A negative FT value indicates that the ECM is reducing the amount of fuel in order to compensate for a rich condition by decreasing the pulse width. A change made to the fuel delivery changes the short term and long term FT values. The short term FT values change rapidly in response to the HO2S signal voltage. These changes fine tune the engine fueling. The long term FT makes coarse adjustments to fueling in order to re-center and restore control to short term FT. A scan tool can be used to monitor the short term and long term FT values. A block of cells contain information arranged in combinations of engine RPM and load for a full range of vehicle operating conditions. The long term FT diagnostic is based on an average of cells currently being used. If the powertrain control module (PCM) detects an excessive lean or rich condition, the ECM will set a FT DTC.

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 1,000 RPM.

Run Mode

The Run Mode has 2 conditions: Open Loop operation and Closed Loop operation. When the engine is first started and the engine speed is above 480 RPM, the system goes into an Open Loop operation. In an Open Loop operation, the 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 a Closed Loop, the ECM adjusts the calculated injector pulse width for each bank of injectors based on the signals from each oxygen sensor.

Acceleration Mode

The 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 driveability.

Deceleration Mode

The engine control module (ECM) monitors changes in the throttle position (TP) and the 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.

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 6 injectors under the following conditions

Ignition OFF - Prevents engine run-on
Ignition ON but no ignition reference signal-Prevents flooding or backfiring
A high engine speed - Above the red line
A high vehicle speed - Above the rated tire speed
The extended high speed closed throttle coastdown - Reduces the emissions and increases engine braking

The ECM will selectively disable the injectors under the following conditions

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 solenoid valve to the atmosphere. The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the control module will command the EVAP purge solenoid valve ON, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent solenoid valve OFF, fresh air is drawn through the vent solenoid valve and the vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge solenoid valve into the intake manifold to be consumed during normal combustion. The control module uses several tests to determine if the EVAP system is leaking.

Large Leak Test

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

Small Leak Test

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

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

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

Canister Vent Restriction Test

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

Purge Solenoid Valve Leak Test

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

Check Gas Cap Message

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

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

EVAP System Components

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

EVAP Canister

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

EVAP Purge Solenoid Valve

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

EVAP Vent Solenoid Valve

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

Fuel Tank Pressure Sensor

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

EVAP Service Port

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

Electronic Ignition (EI) System Operation

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

Crankshaft Position (CKP) Sensor

The crankshaft position (CKP) sensor is a hall-effect sensor. An integrated circuit (IC) magnetic sensing element inside the sensor is magnetically biased by a permanent magnet located within the sensor. The CKP sensor circuits consist of a 12-volt reference circuit, a low reference circuit, and a signal circuit. The CKP sensor produces a DC voltage of varying amplitude and frequency. The frequency depends on the velocity of the crankshaft and the DC output voltage depends on the crankshaft position and battery voltage. The CKP sensor works in conjunction with a 58-tooth reluctor wheel attached to the crankshaft. As each reluctor wheel tooth rotates past the CKP sensor, the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The sensor returns a digital ON/OFF pulse 58 times per crankshaft revolution. The engine control module (ECM) processes the digital pulse to create a signature pattern that enables the ECM to determine the crankshaft position. The CMP sensor signal is used to determine the position of the valve train relative to the crankshaft position. The ECM can synchronize the ignition timing, the fuel injector timing, and the spark knock control based on the CKP sensor and CMP sensor inputs. The CKP sensor is also used to detect misfire.

Crankshaft Reluctor Wheel

The crankshaft reluctor wheel is part of the crankshaft. The reluctor wheel consists of 58 teeth and a reference gap. Each tooth on the reluctor wheel is spaced 6 degrees apart with a 12-degree space for the reference gap. The reference gap is used to determine the crankshaft position (CKP), while the other teeth provide cylinder location during a revolution.

Camshaft Position (CMP) Sensor

The camshaft position (CMP) sensor is a hall ignition control (IC) type sensor. The sensor is true power on (TPO) at power up, which means it is capable of recognizing whether it is in front of a tooth or a notch at power up, and to set its output accordingly. The sensor is a high technology product that integrates a self calibrating system that compensates for environmental changes, such as temperature and air gap. The sensor is composed of a magneto-electronic module that generates a magnetic signal and transforms it into a digital signal. The sensor operates in 2 functional modes. The first mode is the static functional mode. This mode is valid at sensor power up. In this mode, the sensor behaves like a simple DC hall IC switch with 2 fixed switching points. The static functional mode is active during the first 10 mechanical edges of the reluctor wheel and as long as the signal frequency is lower than 1.2 Hertz, plus or minus 0.5 Hertz, with the one tooth reluctor wheel. When the signal frequency exceeds the previous mentioned limit, the sensor switches to the second functional mode, the self-calibrating functional mode. This mode enables the sensor to reach high angular position accuracy, which is not possible to achieve in the static functional mode. In the self-calibrating mode, the sensor acts as a field induction sensor, which is more accurate at higher engine RPM. The sensor switches from self-calibrating mode to static functional mode when the signal frequency becomes lower than 0.3 Hertz, plus or minus 0.1 Hertz, with the 1-tooth reluctor wheel. When the sensor switches back from self-calibrating mode to the TPO mode, a pulse of short duration is generated on the sensor output signal. The pulse may occur on the low signal state or on the high signal state.

The CMP sensor wiring consists of a 12-volt reference circuit, a low reference circuit, and a signal circuit. The CMP sensors work in conjunction with a 1-tooth reluctor wheel on the exhaust CMP actuators. The CMP sensors work in conjunction with an 8-tooth reluctor wheel on the intake CMP actuators. As each tooth on the reluctor wheel passes the CMP sensor it sends a digital signal, which is an image of the wheel, to the engine control module (ECM). The ECM processes this information to determine the exact position of the camshafts, and to determine the optimum ignition and injection points of the engine.

Camshaft Reluctor Wheels

The camshaft reluctor wheel is part of the camshaft position (CMP) actuator. This system consists of 2 different reluctor wheels. One for the exhaust camshafts on bank 1 and bank 2 and one for the intake camshafts on bank 1 and bank 2. The reluctor wheel on the exhaust CMP actuators has one tooth that extends 175 degrees around the circumference of the wheel. The reluctor wheel on the intake CMP actuators is an 8-tooth wheel that consists of 4 long and 4 short high and low phases. The 8X reluctor wheel is also used for the limp home mode.

Ignition Coil/Module

Each ignition coil/module has the following circuits

An ignition voltage circuit
A ground
An ignition control (IC) circuit
A low reference circuit

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

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

Knock Sensor

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

This KS system uses one or 2 flat response 2-wire sensors. The sensor uses piezo-electric crystal technology that produces an AC voltage signal of varying amplitude and frequency based on the engine vibration or noise level. The amplitude and frequency are dependant upon the level of knock that the KS detects. The control module receives KS signal through a signal circuit. The KS ground is supplied by the control module through a low reference circuit.

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

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

Engine Control Module (ECM)

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

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 sensor (KS)

Modes of Operation

During normal operation, the engine control module (ECM) controls all ignition functions. If either the crankshaft position (CKP) or the camshaft position (CMP) sensor signal is lost, the engine will continue to run because the ECM will default to a limp-home mode using the remaining sensor input. Each coil is internally protected against damage from excessive voltage. Diagnostic trouble codes are available to accurately diagnose the ignition system with a scan tool.

Purpose

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

Sensor Description

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

Air Intake System Description

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

Special Tools

Special Tools Illustration Tool Number/ Description GE-41415-50 Fuel Tank Cap Adapter J 22610 Keystone Clamp Pliers J 23738-A Mityvac J 26792/BT-7220-1 Spark Tester J 34730-1A Fuel Pressure Gage J 35616-A/BT-8637 Connector Test Adapter Kit J 36012-A Ignition System Diagnostic Harness J 37088-A Fuel Line Disconnect Tool Set J 37287 Inlet and Return Fuel Line Shut-Off Adapters J 38522 Variable Signal Generator J 39021 Fuel Injector Coil/Balance Tester J 39765 Fuel Sender Locknut Wrench J 41413-200 Evaporative Emissions System Tester (EEST) J 41413-300 EVAP Cap and Plug Kit J 41413-306 EVAP Plug J 41413-307 EVAP Plug J 41413-311 EVAP Plug J 41413-SPT High Intensity White Light J 41413-VLV EVAP Service Port Vent Fitting J 41416 Ultrasonic Leak Detector J 41415-40 Fuel Tank Cap Adapter J 42598-B Vehicle Data Recorder J 42960-2 Fuel Flapper Door Holder J 43094 Spark Plug Boot Puller J 43244 Relay Puller Pliers J 44175 Fuel Composition Tester J 44581 Fuel Line Disconnect Tool Set J 44602 Injector Test Adapter J 44603 Injector Test Lamp J 45004 Fuel Tank Drain Hose J 45289 CANdi Module J 45747 Fuel Sender Lock Nut Wrench