Important Preliminary Inspections Before Beginning
Before using this section, perform the Diagnostic System Check - Engine Controls and verify all of the following conditions
- Diagnostic trouble codes (DTCs) are not stored.
- The scan tool data is within the normal operating range. Refer to «Scan Tool Data List»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-diagnostic-information-procedures__scan-tool-data-list) .
- Verify the customer concern and locate the correct symptom table. Inspect the items indicated in that symptom table.
- Several of the symptom procedures ask for a careful visual/physical inspection. This step is extremely important, and can lead to correcting a condition without further inspections and can save valuable time.
- If the intermittent condition exists as a start and then stall, inspect for any DTCs related to the theft deterrent system. Refer to «Diagnostic System Check - Theft Deterrent»(/cadillac/cts/i-2002-2007/remont/door-locks-anti-theft-systems/#theft-deterrent-system) in Theft Deterrent.
- Verify the proper installation of any of the following aftermarket accessories: Lights Cellular phone Remote starter system Aftermarket installed alarm
- Use the following tables when diagnosing a symptom concern: «Poor Fuel Fill Quality»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__poor-fuel-fill-quality) «Hard Start»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__hard-start) «Surges/Chuggles»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__surgeschuggles) «Lack of Power, Sluggishness, or Sponginess»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__lack-of-power-sluggishness-or-sponginess) «Detonation/Spark Knock»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__detonationspark-knock) «Hesitation, Sag, Stumble»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__hesitation-sag-stumble) «Cuts Out, Misses»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__cuts-out-misses) «Poor Fuel Economy»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__poor-fuel-economy) «Rough, Unstable, or Incorrect Idle and Stalling»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__rough-unstable-or-incorrect-idle-and) «Dieseling, Run-On»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__dieseling-run-on) «Backfire»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__backfire)
- If the condition cannot be isolated using the appropriate table, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__intermittent-conditions) for further diagnosis.
Intermittent Conditions
| Inspections | Action |
|---|---|
| DEFINITION: The condition is not currently present but is indicated in the DTC history. OR There is a customer concern, but the symptom cannot currently be duplicated, if the condition is not DTC related. | |
| Preliminary | Refer to Important Preliminary Inspection Before Beginning in Symptoms - Engine Controls. The fault must be present to locate a problem using the DTC table. If a fault is intermittent, the use of DTC tables may result in the replacement of good parts. |
| Visual/Physical | This step is an important aid for locating a condition without extensive testing. Perform a thorough visual and physical inspection of the following components: Wiring harness for damage or cuts A misrouted harness that is too close to high voltage or high current devices such as the following: Secondary ignition components Motors Generators Vacuum hoses for the following conditions: Proper routing Proper connections Splits in the hose or the connections Kinks The control module and body grounds are clean and tight. Battery connections are clean and tight. Charging system for proper operation-Refer to Charging System Test (With RVC) in Engine Electrical. |
| Harness/Connector Test | Many intermittent open or shorted circuits come and go with harness and connector movement caused by vibration, engine torque, bumps and rough pavement, etc. Test for this type of condition by performing the applicable procedure from the following list: Move the related connectors and wiring while monitoring the appropriate scan tool data. Move the related connectors and wiring with the component commanded ON and OFF, with the scan tool. Observe the components operation. With the engine running, move the related connectors and wiring while monitoring engine operation. If harness or connector movement affects the data displayed, the component and system operation, or the engine operation, inspect and repair the harness or connections as necessary. |
| Electrical Connections or Wiring | Poor electrical connections and terminal tension or wiring faults cause most intermittents. Perform a careful inspection of the suspected circuit for the following: Inspect for incorrect mating of the connector halves, or terminals not fully seated in the connector body, backed-out. Inspect for improperly formed or damaged terminals. Test for incorrect terminal tension. Inspect for poor terminal to wire connections including terminals crimped over insulation. This requires removing the terminal from the connector body. Inspect for corrosion or water intrusion. Pierced or damaged insulation can allow moisture to enter the wiring. The conductor can corrode inside the insulation with little visible evidence. Look for swollen and stiff sections of wire in the suspect circuits. Inspect for wires that are broken inside the insulation. Inspect the harness for pinched, cut, or rubbed through wiring. Make sure the wiring does not come in contact with hot exhaust components. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. |
| Control Module Power and Grounds | Poor power or ground connections can cause widely varying symptoms. Test all control module power circuits. Many vehicles have multiple circuits supplying power to the control module. Inspect connections at the control module connectors, fuses, and any intermediate connections between the power source and the control module or component. A test lamp or a DMM may indicate that voltage is present, but neither tests a circuits ability to carry sufficient current. Ensure that the circuit can carry the current necessary to operate the component. Refer to Power Distribution Schematics in Wiring Systems. Test all control module ground and system ground circuits. The control module may have multiple ground circuits. Other components in the system may have separate grounds that may also need to be tested. Make sure the ground connections are clean and tight at the grounding point. Inspect the connections at the component and in splice packs, where applicable. Ensure that the circuit can carry the current necessary to operate the component. |
| Temperature Sensitivity | An intermittent condition may occur only when the component is cold, or only when the component is hot. The heat that affects the circuit can be engine generated or due to a poor connection in the circuit or a high electrical load. Information from the customer may help to determine if the trouble follows a pattern that is temperature related. The Freeze Frame/Failure Records or Snapshot data may help with this type of intermittent condition, where applicable. If the intermittent is related to heat, review the data for a relationship with the following: High ambient temperatures Underhood/engine generated heat Circuit generated heat due to a poor connection, or high electrical load Higher than normal load conditions (towing, etc.) If the intermittent is related to cold, review the data for the following: Low ambient temperatures-In extremely low temperatures, ice may form in a connection or component. Inspect for water intrusion. The condition only occurs on a cold start. The condition goes away when the vehicle warms up. |
| Electromagnetic Interference (EMI) and Electrical Noise | Some electrical components and circuits are sensitive to electromagnetic interference (EMI) or other types of electrical noise. Inspect for the following conditions: A misrouted harness that is too close to high voltage and high current devices such as secondary ignition components, motors, generator, etc. These components may induce electrical noise on a circuit that could interfere with normal circuit operation. Electrical system interference caused by a malfunctioning relay, control module driven solenoid, or switch. They can cause a sharp electrical surge. Normally, the problem will occur when the malfunctioning component is operating. Incorrect installation of non-factory, aftermarket, add-on accessories such as lights, 2-way radios, amplifiers, electric motors, remote starters, alarm systems, cell phones, etc. Test for an open diode across the A/C compressor clutch and for other open diodes. Some relays may contain a clamping diode or resistor. |
| Incorrect Control Module Programming | There are only a few situations where reprogramming a control module is appropriate: A new control module is installed. Revised software/calibration files have been released for this vehicle. IMPORTANT: DO NOT reprogram the control module with the SAME software/calibration files that are already present in the control module. This is not an effective repair for any type of driveability problem. Verify that the control module contains the correct software/calibration. If incorrect programming is found, reprogram the control module with the most current software/calibration. Refer to Service Programming System (SPS) in Programming and Setup. |
| Duplicating Failure Conditions | If the previous tests were not successful, attempt to duplicate and/or capture the failure conditions. Freeze Frame/Failure Records data, where applicable, contains the conditions that were present when the DTC set. Review and record the Freeze Frame/Failure Records data. Clear any DTCs with a scan tool. Turn OFF the key and wait 15 seconds. Operate the vehicle under the same conditions that were noted in Freeze Frame/Failure Records. The vehicle must also be operating within the Conditions For Running the DTC. Refer to Conditions for Running the DTC in the supporting text of the DTC being diagnosed. Monitor DTC status for the DTC being tested. The scan tool will indicate Ran when the enabling conditions have been satisfied long enough for the DTC to run. The scan tool will also indicate whether the DTC passed or failed. An alternate method is to drive the vehicle with a DMM connected to a suspected circuit. An abnormal reading on the DMM when the problem occurs may help you locate the problem. |
| Scan Tool Snapshot | The scan tool can be set up to take a snapshot of the parameters available via serial data. The Snapshot function records live data over a period of time. The recorded data can be played back and analyzed. The scan tool can also graph parameters singly or in combinations of parameters for comparison. The snapshot can be triggered manually at the time the symptom is noticed or set up in advance to trigger when a DTC sets. An abnormal value captured in the recorded data may point to a system or component that needs to be investigated further. Refer to the scan tool user instructions for more information on the Snapshot function. |
| IMPORTANT |
|---|
| DO NOT reprogram the control module with the SAME software/calibration files that are already present in the control module. This is not an effective repair for any type of driveability problem. |
Intermittent Conditions
Hard Start
| Inspection/Test | Action |
|---|---|
| DEFINITION: Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies. | |
| Preliminary | Refer to Important Preliminary Inspections Before Beginning in Symptoms - Engine Controls . Verify that the powertrain control module (PCM) grounds are clean, tight, and in the proper locations. Refer to Power and Grounding Component Views in Wiring Systems, and Engine Controls Schematics . Search for bulletins. |
| Sensor/System | Verify that the engine coolant temperature (ECT) sensor is not shifted in value. Connect a scan tool. Compare the engine coolant temperature to the intake air temperature (IAT) on a cold engine. The ECT and IAT sensor values should be within +/- 3°C (5°F) of each other. If the ECT sensor is out of range with the IAT sensor, measure the resistance of the ECT sensor. Refer to Temperature vs Resistance for resistance specifications. Inspect for proper operation of the MAP sensor. Refer to DTC P0106 . IMPORTANT: The embossed arrows on the mass air flow (MAF) sensor indicate the direction of the intake air flow. The arrows must point toward the engine. Install the MAF in the proper direction. Refer to Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement . Inspect the MAF sensor installation. A MAF sensor that is incorrectly installed may cause a hard start. Inspect the camshaft position (CMP) sensor for proper mounting and/or a bad connection. An extended crank occurs if the PCM does not receive a CMP signal. |
| Fuel System | Verify there is adequate fuel. Inspect the fuel pump relay operation. The fuel pump should turn ON for 2 seconds when you turn ON the ignition. Refer to Fuel Pump Electrical Circuit Diagnosis . A faulty in-tank fuel pump check valve allows the fuel in the lines to drain back to the tank after the engine stops. Refer to Fuel System Diagnosis . Verify that both fuel injector fuses are not open. An open fuel injector fuse causes four injectors and four ignition coils not to operate. Inspect the injector circuits and the ignition coil circuits for an intermittent short to ground. Replace the fuse. Refer to Circuit Testing in Wiring Systems. Test the fuel injectors. Refer to Fuel Injector Coil Test . Inspect for incorrect fuel pressure. Refer to Fuel System Diagnosis . Inspect for a restricted fuel filter. Refer to Fuel System Diagnosis . Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . |
| Ignition System | Verify that both fuel injector fuses are not open. An open fuel injector fuse causes 4 ignition coils and 4 fuel injectors not to operate. Inspect the ignition coil circuits and the fuel injector circuits for an intermittent short to ground. Refer to Circuit Testing in Wiring Systems. Replace the fuse. Inspect for proper ignition voltage output with the J 26792 Spark Tester. Refer to Electronic Ignition (EI) System Diagnosis . Remove the spark plugs and inspect for the following: Correct heat range Wet plugs Cracks Wear Improper gap Burned electrodes Heavy deposits Refer to Spark Plug Replacement . Refer to Spark Plug Inspection and Ignition System Specifications . Determine the cause of the conditions before replacing the spark plugs. Inspect for bare or shorted ignition wires. Refer to Spark Plug Wire Inspection . Inspect for loose ignition coil grounds. Refer to Electronic Ignition (EI) System Diagnosis . |
| Engine Mechanical | Inspect for the following conditions: Excessive oil in combustion chamber or leaking valve seals-Refer to Oil Consumption Diagnosis in Engine Mechanical. Low cylinder compression-Refer to Engine Compression Test in Engine Mechanical. Improper valve timing Combustion chambers for excessive carbon buildup-Clean the chambers using top engine cleaner. Follow the instructions on the can. Incorrect and worn or damaged basic engine parts-Inspect the following: Cylinder heads-Refer to Cylinder Head Cleaning and Inspection . Camshaft-Refer to Camshaft and Bearings Cleaning and Inspection . Pistons, etc.-Refer to Piston, Connecting Rod, and Bearings Cleaning and Inspection . Inspect for excessive crankshaft endplay that will cause the crankshaft position (CKP) sensor reluctor wheel to move out of alignment with the CKP sensor. Refer to Crankshaft and Bearings Cleaning and Inspection in Engine Mechanical. This could result in any of the following conditions: A no start A start and stall Erratic performance |
| IMPORTANT |
|---|
| The embossed arrows on the mass air flow (MAF) sensor indicate the direction of the intake air flow. The arrows must point toward the engine. Install the MAF in the proper direction. Refer to Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement . |
Hard Start
Surges/Chuggles
| Inspection/Tests | Action |
|---|---|
| DEFINITION: Engine power variation under steady throttle or cruise. Feels like the vehicle speeds up and slows down with no change in the accelerator pedal position. | |
| Preliminary | Refer to Important Preliminary Inspections Before Beginning in Symptoms - Engine Controls . Search for bulletins. Inspect the powertrain control module (PCM) grounds for being clean, tight, and in the proper locations. Refer to Power and Grounding Component Views in Wiring Systems and Engine Controls Schematics . Verify the driver understands the operation of the A/C compressor operation as explained in the owners manual. Inform the customer how the A/C clutch operates. |
| Sensor/System | NOTE: Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices. Inspect for an engine coolant temperature (ECT) sensor that has shifted in value. Refer to Temperature vs Resistance . Inspect for proper operation of the manifold absolute pressure (MAP) sensor. Refer to DTC P0106 . |
| Fuel System | Test for incorrect fuel pressure. Refer to Fuel System Diagnosis . Inspect for a restricted fuel filter. Refer to Fuel System Diagnosis . Test the fuel injectors. Refer to Fuel Injector Coil Test . Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Verify that each injector harness is connected to the correct injector or cylinder. Relocate injector harnesses as necessary. Inspect for the following that may cause the engine to run rich: NOTE: Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. Water intrusion in the heated oxygen sensor (HO2S) connector Engine oil contaminated by fuel An evaporative emission (EVAP) canister purge condition Incorrect fuel pressure-Refer to Fuel System Diagnosis . A leaking fuel pressure regulator-Refer to Fuel System Diagnosis . Leaking fuel injectors-Refer to Fuel System Diagnosis . MAP sensor operation-Refer to DTC P0106 Vacuum hoses that are split, kinked, improperly connected or routed-Refer to Emission Hose Routing Diagram . An air intake duct that is collapsed or restricted An air filter that is dirty or restricted-Refer to Air Cleaner Element Replacement . Inspect for the following conditions that may cause the engine to run lean: NOTE: Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. Water intrusion in the HO2S connector An exhaust leak between the HO2S and the engine-Refer to Exhaust Leakage in Engine Exhaust. Vacuum leaks Incorrect fuel pressure-Refer to Fuel System Diagnosis . Restricted fuel injectors-Refer to Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2 . MAP sensor operation-Refer to DTC P0106 . Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Vacuum hoses that are split, kinked, improperly connected or routed-Refer to Emission Hose Routing Diagram . |
| Ignition System | Soak the secondary ignition system with water from a spray bottle. Soaking the secondary ignition system may help locate damaged or deteriorated components. Look and listen for arcing or misfiring as you apply the water. Test for proper ignition voltage output with the J 26792 Spark Tester. Refer to Electronic Ignition (EI) System Diagnosis . Remove the spark plugs and inspect for the following: Correct heat range Wet plugs Cracks Wear Improper gap Burned electrodes Heavy deposits Refer to Spark Plug Replacement . Refer to Spark Plug Inspection and Ignition System Specifications . An improper spark plug gap will cause a driveability problem. Gap the spark plugs using a wire gage gap tool. Refer to Spark Plug Replacement . Determine the cause of the fouling before replacing the spark plugs. Monitor the Misfire Current Counters while driving the vehicle within the conditions that the misfire occurred. If a misfiring cylinder can be located, use the DTC P0300 table for diagnosis. Refer to DTC P0300 . Inspect for loose ignition coil grounds. Refer to Electronic Ignition (EI) System Diagnosis . |
| Engine Mechanical | Inspect for excessive crankshaft endplay that will cause the crankshaft position (CKP) sensor reluctor wheel to move out of alignment with the CKP sensor. Refer to in Engine Mechanical. This could result in any of the following conditions: A no start A start and stall Erratic performance |
| Additional Inspections | Visually and physically inspect vacuum hoses for splits, kinks, and proper connections and routing as shown on the Vehicle Emission Control Information label. Refer to Emission Hose Routing Diagram . |
| NOTE |
|---|
| Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices. |
| NOTE |
|---|
| Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. |
| NOTE |
|---|
| Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. |
Surges/Chuggles
Lack of Power, Sluggishness, or Sponginess
| Inspection/Tests | Action |
|---|---|
| DEFINITION: Engine delivers less than expected power. Little or no increase in speed when the accelerator pedal is pushed down part way. | |
| Preliminary Inspections | Refer to Important Preliminary Inspections Before Beginning in Symptoms - Engine Controls . Search for bulletins. Verify that the powertrain control module (PCM) grounds are clean, tight, and in the proper locations. Refer to Power and Grounding Component Views in Wiring Systems and Engine Controls Schematics . Remove the air filter element and inspect for dirt or for restrictions. Refer to Air Cleaner Element Replacement and replace as necessary. |
| Fuel System | Inspect both injector fuses for being open. An open injector fuse causes four ignition coils and four injectors not to operate. Replace the fuse. Inspect the ignition coil circuits and the injector circuits for an intermittent short to ground. Inspect for incorrect fuel pressure. Refer to Fuel System Diagnosis . Inspect for a restricted fuel filter. Refer to Fuel System Diagnosis . Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Inspect the fuel injectors. Refer to Fuel Injector Coil Test , Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2 . Inspect for the following that may cause the engine to run rich: NOTE: Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. Water intrusion in the heated oxygen sensor (HO2S) connector Engine oil contaminated by fuel An evaporative emission (EVAP) canister purge condition Incorrect fuel pressure-Refer to Fuel System Diagnosis . A leaking fuel pressure regulator-Refer to Fuel System Diagnosis . Leaking fuel injectors-Refer to Fuel System Diagnosis . Vacuum hoses that are split, kinked, or improperly connected An air intake duct that is collapsed or restricted An air filter that is dirty or restricted-Refer to Air Cleaner Element Replacement . Inspect for the following conditions that may cause the engine to run lean: NOTE: Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. Water intrusion in the HO2S connector An exhaust leak between the HO2S and the engine-Refer to Exhaust Leakage in Engine Exhaust. Vacuum leaks Incorrect fuel pressure-Refer to Fuel System Diagnosis . Restricted fuel injectors-Refer to Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2 . Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Vacuum hoses that are split, kinked, or improperly connected |
| Sensor/System | Use a scan tool in order to monitor the knock sensor (KS) system for excessive spark retard activity. Refer to Knock Sensor (KS) System Description . |
| Ignition System | Verify that both fuel injector fuses are not open. An open fuel injector fuse causes four ignition coils and four fuel injectors not to operate. Inspect the ignition coil circuit and the injector circuits for an intermittent short to ground. Refer to Circuit Testing in Wiring Systems. Replace the fuse. Soak the secondary ignition system with water from a spray bottle. Soaking the secondary ignition system may help locate damaged or deteriorated components. Look and listen for arcing or misfiring as water is applied. Monitor the Misfire Current Counters while driving the vehicle within the conditions that the misfire occurred. If a misfiring cylinder can be located with a misfire, use the DTC P0300 table for diagnosis. Refer to DTC P0300 . Inspect for proper ignition voltage output with the J 26792 Spark Tester. Remove the spark plugs and inspect for the following: Correct heat range Wet plugs Cracks Wear Improper gap Burned electrodes Heavy deposits Refer to Spark Plug Replacement . Refer to Spark Plug Inspection and Ignition System Specifications . Determine the cause of the fouling before replacing the spark plugs. Inspect for loose ignition coil grounds. Refer to Electronic Ignition (EI) System Diagnosis . |
| Engine Mechanical | Inspect for excessive oil in the combustion chambers and leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical. Test for low cylinder compression. Refer to Engine Compression Test in Engine Mechanical. Inspect for incorrect, worn or damaged basic engine parts, including the following: The camshaft-Refer to Crankshaft and Bearings Cleaning and Inspection in Engine Mechanical. The cylinder heads-Refer to Cylinder Head Cleaning and Inspection in Engine Mechanical. The pistons, etc.-Refer to Piston, Connecting Rod, and Bearings Cleaning and Inspection in Engine Mechanical. Inspect for excessive crankshaft endplay that will cause the crankshaft position (CKP) sensor reluctor wheel to move out of alignment with the CKP sensor. Refer to Crankshaft and Bearings Cleaning and Inspection in Engine Mechanical. This could result in any of the following conditions: A no start A start and stall Erratic performance |
| Additional Inspections | Inspect the exhaust system for possible restrictions. Perform the following: Inspect the exhaust system for damaged or collapsed pipes. Inspect the mufflers for heat distress or internal failure. Inspect for plugged catalytic converters. Refer to Restricted Exhaust in Engine Exhaust. |
| NOTE |
|---|
| Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. |
| NOTE |
|---|
| Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. |
Lack of Power, Sluggishness, or Sponginess
Detonation/Spark Knock
| Inspection/Tests | Action |
|---|---|
| DEFINITION: A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with throttle opening. | |
| Preliminary Inspections | Refer to Important Preliminary Inspections Before Beginning in Symptoms - Engine Controls . Search for bulletins. Verify that the powertrain control module (PCM) grounds are clean, tight, and in the proper locations. Refer to Power and Grounding Component Views in Wiring Systems and Engine Controls Schematics . If there are no engine mechanical faults, fill the fuel tank with a known high quality fuel that meets the vehicles minimum octane requirements. Road test the vehicle and re-evaluate the vehicles performance. |
| Fuel System | Inspect for incorrect fuel pressure. Refer to Fuel System Diagnosis . Inspect for a restricted fuel filter. Refer to Fuel System Diagnosis . Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Inspect the fuel injectors. Refer to Fuel Injector Coil Test . Inspect for the following conditions that may cause the engine to run lean: NOTE: Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. Water intrusion in the heated oxygen sensor (HO2S) connector An exhaust leak between the HO2S and the engine-Refer to Exhaust Leakage in Engine Exhaust. Vacuum leaks Incorrect fuel pressure-Refer to Fuel System Diagnosis . Restricted fuel injectors-Refer to Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2 . Manifold absolute pressure (MAP) sensor operation-Refer to DTC P0106 . Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Vacuum hoses that are split, kinked, or improperly connected |
| Ignition System | Verify that the spark plugs are of the proper heat range. Refer to Spark Plug Inspection . |
| Engine Cooling System | Inspect for obvious overheating problems: Low engine coolant-Refer to Loss of Coolant (M 35) or Loss of Coolant (M 82) in Engine Cooling for the type and amount of engine coolant to be used. Restricted air flow to the radiator or restricted coolant flow through the radiator. Proper tension on the drive belts-Refer to Drive Belt Tensioner Diagnosis . Inoperative cooling fan-Refer to Cooling Fan Inoperative . |
| Engine Mechanical | Inspect for the following engine mechanical problems: Excessive oil in combustion chamber-Leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical. Incorrect cylinder compression-Refer to Engine Compression Test Engine Mechanical. Combustion chambers for excessive carbon buildup-Clean the combustion chamber by using top engine cleaner. Follow the instructions on the can. Inspect for incorrect, worn or damaged basic engine parts. Inspect the following: The camshaft-Refer to Crankshaft and Bearings Cleaning and Inspection in Engine Mechanical. The cylinder heads-Refer to Cylinder Head Cleaning and Inspection in Engine Mechanical. The pistons, etc.-Refer to Piston, Connecting Rod, and Bearings Cleaning and Inspection in Engine Mechanical. Refer to Symptoms - Engine Mechanical in Engine Mechanical. |
| NOTE |
|---|
| Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. |
Detonation/Spark Knock
Hesitation, Sag, Stumble
| Inspection/Tests | Action |
|---|---|
| DEFINITION: Momentary lack of response as the accelerator is pushed down. Can occur at any vehicle speed. Usually more pronounced when first trying to make the vehicle move, as from a stop. May cause the engine to stall if severe enough. | |
| Preliminary | Refer to Important Preliminary Inspections Before Beginning in Symptoms - Engine Controls . Search for bulletins. Verify that the powertrain control module (PCM) grounds are clean, tight, and in the proper locations. Refer to Engine Controls Schematics . |
| Sensor/System | Inspect the manifold absolute pressure (MAP) sensor operation. Refer to DTC P0106 . An extended travel brake switch that is mis-adjusted or an extended travel brake circuit that is open causes a perceived misfire under heavy load conditions from a stop. Use a scan tool in order to monitor the extended travel brake switch parameter. |
| Fuel System | Inspect for incorrect fuel pressure. Refer to Fuel System Diagnosis . Inspect for a restricted fuel filter. Refer to Fuel System Diagnosis . Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Verify that both fuel injector fuses are not open. An open fuel injector fuse causes four ignition coils and four fuel injectors not to operate. Inspect the ignition coil circuits and the fuel injector circuits for an intermittent short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Replace the fuse. Inspect the fuel injectors. Refer to Fuel Injector Coil Test . Inspect for the following that may cause the engine to run rich: NOTE: Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. Water intrusion in the heated oxygen sensor (HO2S) connector Engine oil contaminated by fuel An evaporative emission (EVAP) canister purge condition Incorrect fuel pressure-Refer to Fuel System Diagnosis . A leaking fuel pressure regulator-Refer to Fuel System Diagnosis . Leaking fuel injectors-Refer to Fuel System Diagnosis . Vacuum hoses that are split, kinked, improperly connected, or routed-Refer to Emission Hose Routing Diagram . An air intake duct that is collapsed or restricted An air filter that is dirty or restricted-Refer to Air Cleaner Element Replacement . Inspect for the following conditions that may cause the engine to run lean: NOTE: Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. Water intrusion in the HO2S connector An exhaust leak between the HO2S and the engine-Refer to Exhaust Leakage in Engine Exhaust. Vacuum leaks Incorrect fuel pressure-Refer to Fuel System Diagnosis . Restricted fuel injectors-Refer to Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2 . Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Vacuum hoses that are split, kinked, improperly connected or routed-Refer to Emission Hose Routing Diagram . |
| Ignition System | Soak the secondary ignition system with water from a spray bottle. Soaking the secondary ignition system may help locate damaged or deteriorated components. Look and listen for arcing or misfiring as you apply water. Monitor the Misfire Current Counters while driving the vehicle in the conditions that the misfire occurred. If a misfiring cylinder can be located, use the DTC P0300 table for diagnosis. Refer to DTC P0300 . Test for proper ignition voltage output with the J 26792 Spark Tester. Refer to Electronic Ignition (EI) System Diagnosis for the procedure. Remove the spark plugs and check for the following: Correct heat range Wet plugs Cracks Wear Improper gap Burned electrodes Heavy deposits Refer to Spark Plug Replacement . Refer to Spark Plug Inspection and Ignition System Specifications . Determine the cause of the fouling before replacing the spark plugs. Inspect for loose ignition coil grounds. Refer to Electronic Ignition (EI) System Diagnosis . |
| Engine Cooling System | Inspect the engine thermostat for proper operation and for proper heat range. Refer to Thermostat Diagnosis (LA3, LY9) , Thermostat Diagnosis (LY7) or Thermostat Diagnosis (LS6) in Engine Cooling. |
| Engine Mechanical | Inspect for excessive crankshaft endplay that will cause the crankshaft position (CKP) sensor reluctor wheel to move out of alignment with the CKP sensor. Refer to Crankshaft and Bearings Cleaning and Inspection in Engine Mechanical. This could result in any of the following conditions: A no start A start and stall Erratic performance |
| Additional Inspections | Inspect the generator output voltage. Refer to Diagnostic System Check - Engine Electrical in Engine Electrical for the procedure. Repair the charging system if the generator output voltage is less than 9 volts or more than 16 volts. |
| NOTE |
|---|
| Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. |
| NOTE |
|---|
| Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. |
Hesitation, Sag, Stumble
Cuts Out, Misses
| Inspections | Action |
|---|---|
| DEFINITION: Steady pulsation or jerking that follows engine speed, usually more pronounced as engine load increases. This condition is not normally felt above 1,500 RPM or 48 km/h (30 mph). The exhaust has a steady spitting sound at idle or low speed. | |
| Preliminary | Refer to Important Preliminary Inspections Before Beginning in Symptoms - Engine Controls . Search for bulletins. Verify that the powertrain control module (PCM) grounds are clean, tight, and in the proper locations. Refer to Power and Grounding Component Views in Wiring Systems and Engine Controls Schematics . Remove the air filter element and inspect for dirt and for restrictions. Refer to Air Cleaner Element Replacement . Replace as necessary. |
| Fuel System | Inspect the fuel injectors. Refer to Fuel Injector Coil Test , Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2 . Inspect for incorrect fuel pressure. Refer to Fuel System Diagnosis . Inspect for a restricted fuel filter. Refer to Fuel System Diagnosis . Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Inspect for the following that may cause the engine to run rich: NOTE: Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. Water intrusion in the heated oxygen sensor (HO2S) connector Engine oil contaminated by fuel An evaporative emission (EVAP) canister purge condition Incorrect fuel pressure-Refer to Fuel System Diagnosis . A leaking fuel pressure regulator-Refer to Fuel System Diagnosis . Leaking fuel injectors-Refer to Fuel System Diagnosis . Manifold absolute pressure (MAP) sensor operation-Refer to DTC P0106 . Vacuum hoses that are split, kinked, improperly connected or routed-Refer to Emission Hose Routing Diagram . An air intake duct that is collapsed or restricted An air filter that is dirty or restricted-Refer to Air Cleaner Element Replacement . Inspect for the following conditions that may cause the engine to run lean: NOTE: Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. Water intrusion in the HO2S connector An exhaust leak between the HO2S and the engine-Refer to Exhaust Leakage in Engine Exhaust. Vacuum leaks Incorrect fuel pressure-Refer to Fuel System Diagnosis . Restricted fuel injectors-Refer to Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2 . MAP sensor operation-Refer to DTC P0106 . Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Vacuum hoses that are split, kinked, improperly connected or routed-Refer to Emission Hose Routing Diagram . |
| Sensor/System | Use a scan tool in order to monitor the knock sensor (KS) system for excessive spark retard activity. An extended travel brake switch that is mis-adjusted or an extended travel brake circuit that is open causes a perceived misfire under heavy load conditions from a stop. Use a scan tool in order to monitor the Extended Travel Brake Switch parameter. |
| Ignition System | Soak the secondary ignition system with water from a spray bottle. Soaking the secondary ignition system may help locate damaged or deteriorated components. Look and listen for arcing or misfiring as you apply water. Monitor the Misfire Current Counters while driving the vehicle in the conditions that the misfire occurred. If a misfiring cylinder can be located, use the DTC P0300 table for diagnosis. Refer to DTC P0300 . Test for proper ignition voltage output with the J 26792 Spark Tester. Remove the spark plugs and inspect for the following: Correct heat range Wet plugs Cracks Wear Improper gap Burned electrodes Heavy deposits Refer to Spark Plug Replacement . Refer to Spark Plug Inspection and Ignition System Specifications . Determine the cause of the fouling before replacing the spark plugs. Visually and physically inspect the secondary ignition for the following: The ignition wires arcing to ground The ignition wires for proper engagement to spark plug The ignition coils for cracks or carbon tracking Refer to Spark Plug Wire Inspection . |
| Engine Mechanical | Inspect engine mechanical for the following: Inspect compression-Refer to Engine Compression Test in Engine Mechanical. Sticking or leaking valves Worn camshaft lobes Valve timing Bent push rods Worn rocker arms Broken valve springs Excessive oil in combustion chamber-Leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical. For incorrect, worn or damaged basic engine parts inspect the following: The camshaft-Refer to Crankshaft and Bearings Cleaning and Inspection in Engine Mechanical. The cylinder heads-Refer to Cylinder Head Cleaning and Inspection in Engine Mechanical. The pistons, etc.-Refer to Piston, Connecting Rod, and Bearings Cleaning and Inspection in Engine Mechanical. Refer to Symptoms - Engine Mechanical in Engine Mechanical for diagnostic procedures. Inspect for excessive crankshaft endplay that will cause the crankshaft position (CKP) sensor reluctor wheel to move out of alignment with the CKP sensor. Refer to Crankshaft and Bearings Cleaning and Inspection in Engine Mechanical. This could result in any of the following conditions: A no start A start and stall Erratic performance |
| Additional Inspections | Inspect the exhaust system for possible restrictions. Inspect for the following: Inspect the exhaust system for damaged or collapsed pipes. Inspect the mufflers for heat distress or possible internal failure. Inspect for possible plugged catalytic converters. Refer to Restricted Exhaust in Engine Exhaust. Electromagnetic interference (EMI) on the reference circuit can cause an engine misfire condition. A sudden increase in indicated RPM with little change in actual engine RPM change indicates EMI is present. Inspect for high voltage components near ignition control circuits if a condition exists. Inspect the intake manifold and the exhaust manifold passages for casting flash. Refer to Intake Manifold Cleaning and Inspection or Exhaust Manifold Cleaning and Inspection in Engine Mechanical. |
| NOTE |
|---|
| Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. |
| NOTE |
|---|
| Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. |
Cuts Out, Misses
Poor Fuel Economy
| Inspections | Action |
|---|---|
| DEFINITION: Fuel economy, as measured by an actual road test, is noticeably lower than expected. Also, fuel economy is noticeably lower than the economy was on this vehicle at one time, as previously shown by an actual road test. | |
| Preliminary | Refer to Important Preliminary Inspections Before Beginning in Symptoms - Engine Controls . Search for bulletins. Verify that the powertrain control module (PCM) grounds are clean, tight, and in the proper locations. Refer to Power and Grounding Component Views in Wiring Systems and Engine Controls Schematics . Inspect the owners driving habits. Is the A/C ON or the Defroster mode ON full time? Are the tires at the correct pressure? Are the tires the correct size? Are there excessively heavy loads being carried? Is the acceleration rate too much, too often? Remove the air filter element and inspect for dirt or for restrictions. Refer to Air Cleaner Element Replacement . Replace as necessary. |
| Fuel System | Inspect the type, quality, and alcohol content of the fuel. Oxygenated fuels have lower energy and may deliver reduced fuel economy. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Inspect the fuel injectors. Refer to Fuel Injector Coil Test , Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2 . Inspect for incorrect fuel pressure. Refer to Fuel System Diagnosis . Inspect for a restricted fuel filter. Refer to Fuel System Diagnosis . Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Inspect that each fuel injector harness is connected to the correct injector and cylinder. Relocate the injector harnesses as necessary. Inspect for foreign material accumulation in the throttle bore, coking on the throttle valve, or on the throttle shaft. Refer to Throttle Body Cleaning Procedure . Inspect for the following that may cause the engine to run rich: NOTE: Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. Water intrusion in the heated oxygen sensor (HO2S) connector Engine oil contaminated by fuel An evaporative emission (EVAP) canister purge condition Incorrect fuel pressure-Refer to Fuel System Diagnosis . A leaking fuel pressure regulator-Refer to Fuel System Diagnosis . Leaking fuel injectors-Refer to Fuel System Diagnosis . Manifold absolute pressure (MAP) sensor operation-Refer to DTC P0106 Vacuum hoses that are split, kinked, improperly connected or routed-Refer to Emission Hose Routing Diagram . An air intake duct that is collapsed or restricted An air filter that is dirty or restricted-Refer to Air Cleaner Element Replacement . |
| Sensor/System | Inspect the air intake system and crankcase for air leaks. Inspect for an inaccurate speedometer. Refer to Symptoms - Instrument Panel, Gages and Console in Instrument Panel, Gages, and Console. Use a scan tool in order to monitor the knock sensor (KS) system for excessive spark retard activity. Refer to Knock Sensor (KS) System Description . |
| Ignition System | Inspect for proper ignition voltage output with the J 26792 Spark Tester. Remove the spark plugs and inspect for the following: Wet plugs Cracks Wear Improper gap Burned electrodes Heavy deposits Refer to Spark Plug Replacement . Refer to Spark Plug Inspection and Ignition System Specifications . Determine the cause of the fouling before replacing the spark plugs. Refer to Spark Plug Inspection . Inspect the spark plug wires. Refer to Spark Plug Wire Inspection . Soaking the secondary ignition system with water from a spray bottle may help locate damaged or deteriorated components. Look and listen for arcing or misfiring as you apply water. Inspect for loose ignition coil grounds. Refer to Electronic Ignition (EI) System Diagnosis . |
| Engine Cooling System | Inspect the engine coolant level for being low. Refer to Loss of Coolant (M 35) or Loss of Coolant (M 82) in Engine Cooling. Inspect the engine thermostat for proper operation and for the correct heat range. Refer to Thermostat Diagnosis (LA3, LY9) , Thermostat Diagnosis (LY7) or Thermostat Diagnosis (LS6) in Engine Cooling. |
| Engine Mechanical | Inspect engine mechanical for the following: Compression-Refer to Engine Compression Test in Engine Mechanical. Sticking or leaking valves Worn camshaft lobes Valve timing Bent push rods Worn rocker arms Broken valve springs Excessive oil in combustion chamber-Leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical. For incorrect, worn or damaged basic engine parts inspect for the following: The camshaft-Refer to Crankshaft and Bearings Cleaning and Inspection in Engine Mechanical. The cylinder heads-Refer to Cylinder Head Cleaning and Inspection in Engine Mechanical. The pistons, etc.-Refer to Piston, Connecting Rod, and Bearings Cleaning and Inspection in Engine Mechanical. Refer to Engine Compression Test in Engine Mechanical for diagnostic procedures. |
| Additional Inspections | Visually and physically check the vacuum hoses for splits, kinks, and proper connections and routing as shown on Vehicle Emission Control Information label. Refer to Emission Hose Routing Diagram . Inspect the exhaust system for a possible restriction. Inspect for the following: Inspect the exhaust system for damaged or collapsed pipes. Inspect the mufflers for heat distress or possible internal failure. Inspect for possible plugged catalytic converters. Refer to Restricted Exhaust in Engine Exhaust. Inspect the intake and the exhaust manifold passages for casting flash. Refer to Intake Manifold Cleaning and Inspection or Exhaust Manifold Cleaning and Inspection in Engine Mechanical. Inspect the brake system for dragging or improper operation. Refer to Diagnostic System Check - Hydraulic Brakes in Hydraulic Brakes. Verify that the vehicle operator does not drive with a foot on the brake pedal. |
| NOTE |
|---|
| Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. |
Poor Fuel Economy
Poor Fuel Fill Quality
| Problem | Causes |
|---|---|
| DEFINITION: Difficulty when refueling the vehicle. | |
| Difficult to fill | The check valve is stuck closed. The fill limiter vent valve is stuck closed. The evaporative emission (EVAP) canister is restricted. The EVAP canister vent solenoid is stuck closed. Restricted EVAP pipes. High Reid vapor pressure High fuel temperature The fuel filler hose/pipe is pinched, kinked or blocked. The fuel feed hose, or crossover hose, is pinched, kinked or blocked. The ignition switch is ON. |
| Over fill | The pressure relief valve in the fill limiter vent valve is stuck open. The pressure relief valve in the fill limiter vent is valve leaking. The fill limiter vent valve is stuck open. The fill limiter vent valve is leaking. |
| Premature shut-off of the fuel dispensing nozzle | The check valve is stuck closed. The fill limiter vent valve is stuck closed. The EVAP canister is restricted. The EVAP canister vent solenoid is stuck closed. Restricted EVAP pipes High Reid vapor pressure High fuel temperature The fuel filler hose/pipe is pinched, kinked or blocked. The fuel feed hose, or crossover hose, is pinched, kinked or blocked. The ignition switch is ON. |
| Fuel spit back | The check valve is stuck open. The check valve is stuck closed. The check valve is leaking. High Reid vapor pressure High fuel temperature |
| Liquid fuel in the EVAP canister | The fill limiter vent valve is stuck open. The fill limiter vent valve is leaking. |
| Liquid fuel leak | The pressure relief valve in the fill limiter vent valve is stuck open. The pressure relief valve in the fill limiter vent valve is leaking. The fuel filler hose is loose or torn. The fuel feed hose, or crossover hose, is loose or torn. The fill limiter vent valve is stuck open. |
| Fuel odor | The pressure relief valve in the fill limiter vent valve is stuck open. The pressure relief valve in the fill limiter vent valve is leaking. The EVAP canister is saturated. |
Poor Fuel Fill Quality
Rough, Unstable, or Incorrect Idle and Stalling
| Inspections | Action |
|---|---|
| DEFINITION: Engine runs unevenly at idle. If severe, the engine or vehicle may shake. Engine idle speed may vary in RPM. Either condition may be severe enough to stall the engine. | |
| Preliminary Inspections | Refer to Important Preliminary Inspections Before Beginning in Symptoms - Engine Controls . Search for bulletins. Verify that the powertrain control module (PCM) grounds are clean, tight, and in the proper locations. Refer to Power and Grounding Component Views in Wiring Systems and Engine Controls Schematics . Remove and inspect the air filter element for dirt or for restrictions. Refer to Air Cleaner Element Replacement . Replace as necessary. |
| Fuel System | Inspect the fuel injectors. Refer to Fuel Injector Coil Test , Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2 . Inspect for incorrect fuel pressure. Refer to Fuel System Diagnosis . Inspect for a restricted fuel filter. Refer to Fuel System Diagnosis . Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Inspect that each fuel injector harness is connected to the correct injector/cylinder. Relocate fuel injector harnesses as necessary. Inspect for the following that may cause the engine to run rich: NOTE: Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. Water intrusion in the heated oxygen sensor (HO2S) connector Engine oil contaminated by fuel An evaporative emission (EVAP) canister purge condition Incorrect fuel pressure-Refer to Fuel System Diagnosis . A leaking fuel pressure regulator-Refer to Fuel System Diagnosis . Leaking fuel injectors-Refer to Fuel System Diagnosis . Manifold absolute pressure (MAP) sensor operation-Refer to DTC P0106 . Vacuum hoses that are split, kinked, or improperly connected An air intake duct that is collapsed or restricted An air filter that is dirty or restricted-Refer to Air Cleaner Element Replacement . Inspect for the following conditions that may cause the engine to run lean: NOTE: Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. Water intrusion in the HO2S connector An exhaust leak between the HO2S and the engine-Refer to Exhaust Leakage in Engine Exhaust. Vacuum leaks Incorrect fuel pressure-Refer to Fuel System Diagnosis . Restricted fuel injectors-Refer to Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2 . MAP sensor operation-Refer to DTC P0106 . Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Vacuum hoses that are split, kinked, or improperly connected-Refer to Emission Hose Routing Diagram . |
| Sensor/System | Inspect the crankcase system. Refer to Crankcase Ventilation System Inspection/Diagnosis in Engine Mechanical. Use a scan tool in order to monitor the knock sensor (KS) system for excessive spark retard activity. |
| Ignition System | Inspect for proper ignition voltage output with the J 26792 Spark Tester. Refer to Electronic Ignition (EI) System Diagnosis for procedure. Remove spark plugs and check for the following: Wet plugs Cracks Wear Improper gap Burned electrodes Heavy deposits Refer to Spark Plug Replacement . Refer to Spark Plug Inspection and Ignition System Specifications . Inspect the spark plug wires. Refer to Spark Plug Wire Inspection . Soak the secondary ignition system with water from a spray bottle. Soaking the secondary ignition system may help locate damaged or deteriorated components. Look and listen for arcing or misfiring as you apply water. Monitor the Misfire Current Counters while driving the vehicle in the conditions that the misfire occurred. If a misfiring cylinder can be located, use the DTC P0300 table for diagnosis. Refer to DTC P0300 . Inspect for loose ignition coil grounds. Refer to Electronic Ignition (EI) System Diagnosis . |
| Engine Mechanical | Inspect engine mechanical for the following: Compression-Refer to Engine Compression Test in Engine Mechanical. Sticking or leaking valves Worn camshaft lobes Valve timing Bent push rods Worn rocker arms Broken valve springs Excessive oil in combustion chamber or leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical. For incorrect, worn or damaged basic engine parts. Inspect the following: The camshaft-Refer to Crankshaft and Bearings Cleaning and Inspection in Engine Mechanical. The cylinder heads-Refer to Cylinder Head Cleaning and Inspection in Engine Mechanical. The pistons, etc.-Refer to Piston, Connecting Rod, and Bearings Cleaning and Inspection in Engine Mechanical. Inspect for excessive crankshaft endplay that will cause the crankshaft position (CKP) sensor reluctor wheel to move out of alignment with the CKP sensor. Refer to Crankshaft and Bearings Cleaning and Inspection in Engine Mechanical. This could result in any of the following conditions: A no start A start and stall Erratic performance Refer to Symptoms - Engine Mechanical in Engine Mechanical for diagnosis procedures. |
| Additional Inspections | Inspect the exhaust system for possible restrictions. Inspect for the following: Inspect the exhaust system for damaged or collapsed pipes. Inspect the mufflers for heat distress or possible internal failure. Inspect for possible plugged catalytic converters. Refer to Restricted Exhaust in Engine Exhaust. Inspect for faulty motor mounts. Refer to in Engine Mechanical. Inspect the intake manifold and the exhaust manifold passages for casting flash. Refer to Intake Manifold Cleaning and Inspection or Exhaust Manifold Cleaning and Inspection in Engine Mechanical. |
| NOTE |
|---|
| Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. |
| NOTE |
|---|
| Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. |
Rough, Unstable, or Incorrect Idle and Stalling
Dieseling, Run-On
| Inspections | Action |
|---|---|
| DEFINITION: Engine continues to run after key is turned OFF, but runs very rough. If the engine runs smooth, inspect the ignition switch and the ignition switch adjustment. | |
| Preliminary Inspections | Refer to Important Preliminary Inspections Before Beginning in Symptoms - Engine Controls . Search for bulletins. Verify that the powertrain control module (PCM) grounds are clean, tight, and in the proper locations. Refer to Power and Grounding Component Views in Wiring Systems and Engine Controls Schematics . |
| Additional Inspections | Remove the spark plugs and inspect for the following: The correct heat range Any heavy deposits Refer to Spark Plug Inspection . |
| Fuel System | Inspect the fuel injectors for a leaking condition. Refer to Fuel System Diagnosis for the proper procedure. |
Dieseling, Run-On
Backfire
| Inspections | Actions |
|---|---|
| DEFINITION: Fuel ignites in the intake manifold or in the exhaust system, making a loud popping noise. | |
| Preliminary Inspections | Refer to Important Preliminary Inspections Before Beginning in Symptoms - Engine Controls . Search for bulletins. Verify that the powertrain control module (PCM) grounds are clean, tight, and in the proper locations. Refer to Power and Grounding Component Views in Wiring Systems and Engine Controls Schematics . |
| Fuel System | Inspect for incorrect fuel pressure. Refer to Fuel System Diagnosis . Inspect for a restricted fuel filter. Refer to Fuel System Diagnosis . Inspect for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Inspect the fuel injectors. Refer to Fuel Injector Coil Test . Verify that each injector harness is connected to the correct injector or cylinder. Relocate injector harnesses as necessary. |
| Sensor/System | Inspect the air intake system and crankcase for air leaks. Use a scan tool in order to monitor the knock sensor (KS) system for excessive spark retard activity. Refer to Knock Sensor (KS) System Description . |
| Ignition System | Inspect for proper ignition voltage output with J 26792 Spark Tester. Remove spark plugs and inspect for the following: Wet plugs Cracks Wear Improper gap Burned electrodes Heavy deposits Refer to Spark Plug Replacement . Refer to Spark Plug Inspection and Ignition System Specifications . Determine the cause of the fouling before replacing the spark plugs. Refer to Spark Plug Inspection for diagnosis. Inspect the spark plug wires. Refer to Spark Plug Wire Inspection . Soak the secondary ignition system with water from a spray bottle. Soaking the secondary ignition system may help locate damaged or deteriorated components. Look and listen for arcing or misfiring as you apply the water. Monitor the Misfire Current Counters while driving the vehicle in the conditions that the misfire occurred. If a misfiring cylinder can be located, use the DTC P0300 table for diagnosis. Refer to DTC P0300 Inspect for loose ignition coil grounds. Refer to Electronic Ignition (EI) System Diagnosis . |
| Engine Cooling System | Inspect the engine coolant level for being low. Refer to Loss of Coolant (M 35) or Loss of Coolant (M 82) in Engine Cooling. Inspect the engine thermostat for proper operation and for the correct heat range. Refer to Thermostat Diagnosis (LA3, LY9) , Thermostat Diagnosis (LY7) or Thermostat Diagnosis (LS6) in Engine Cooling. |
| Engine Mechanical | Inspect engine mechanical for the following: Compression-Refer to Engine Compression Test in Engine Mechanical. Sticking or leaking valves Worn camshaft lobes Valve timing Bent push rods Worn rocker arms Broken valve springs Excessive oil in combustion chamber or leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical. For incorrect, worn or damaged basic engine parts. Inspect the following: The camshaft-Refer to Crankshaft and Bearings Cleaning and Inspection in Engine Mechanical. The cylinder heads-Refer to Cylinder Head Cleaning and Inspection in Engine Mechanical. The pistons, etc.-Refer to Piston, Connecting Rod, and Bearings Cleaning and Inspection in Engine Mechanical. Refer to Symptoms - Engine Mechanical in Engine Mechanical for diagnosis procedures. |
| Additional Inspections | Visually and physically inspect the vacuum hoses for splits, kinks, and proper connections and routing as shown on the Vehicle Emission Control Information label. Refer to Emission Hose Routing Diagram . Inspect the intake manifold and the exhaust manifold passages for casting flash. Refer to Intake Manifold Cleaning and Inspection or Exhaust Manifold Cleaning and Inspection in Engine Mechanical. Inspect the exhaust system for possible restrictions. Inspect the following: Inspect the exhaust system for damaged or collapsed pipes. Inspect the mufflers for heat distress or possible internal failure. Inspect for possible plugged catalytic converters. Refer to Restricted Exhaust in Engine Exhaust. |
Backfire
Description
The Engine Cranks but Does Not Run diagnostic table is an organized approach to identifying a condition that causes an engine to not start. The diagnostic table directs the service technician to the appropriate system diagnosis. The diagnostic table assumes the following conditions are met
- The battery is completely charged. Refer to «Battery Inspection/Test»(/cadillac/cts/i-2002-2007/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
- The engine cranking speed is acceptable. Refer to «Engine Cranks Slowly»(/cadillac/cts/i-2002-2007/remont/charging-system/#battery-charging-system-and-starting-system__engine-cranks-slowly) in Engine Electrical.
- There is adequate fuel in the fuel tank.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls | |
| 2 | Turn ON the ignition, with the engine OFF. Observe the DTC information with a scan tool. Does the scan tool display DTCs P0101, P0108, P0230, P0335, P0336, P0601, P0602, P0604, P0606, P0641, P1626, or P1631? | Go to Diagnostic Trouble Code (DTC) List | Go to Step 3 | |
| 3 | Does the scan tool display any body control module (BCM) or vehicle theft deterrent (VTD) DTCs? | Go to Diagnostic System Check - Theft Deterrent in Theft Deterrent | Go to Step 4 | |
| 4 | Turn ON the ignition, with the engine OFF. Probe both sides of the fuses located in the underhood electrical center listed below using a test lamp connected to ground. ODD INJR/Coil EVEN INJR/Coil Does the test lamp illuminate on at least one side of each fuse? | Go to Step 5 | Go to Main Relay Circuit Diagnosis | |
| 5 | Command the fuel pump ON with a scan tool. Does the fuel pump operate? | Go to Step 6 | Go to Fuel Pump Electrical Circuit Diagnosis | |
| 6 | Turn OFF the ignition. Disconnect a spark plug wire. Install J 26792 Spark Tester. Attempt to start the engine. Does the spark tester spark? | Go to Step 7 | Go to Electronic Ignition (EI) System Diagnosis | |
| 7 | Turn OFF the ignition. Install a fuel pressure gauge. Refer to Fuel Pressure Gage Installation and Removal . IMPORTANT: You may need to command the fuel pump ON a few times in order to obtain the highest possible fuel pressure. Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Observe the fuel pressure while the fuel pump is operating. Is the fuel pressure within the specified range? | 379-427 kPa (55-62 psi) | Go to Step 8 | Go to Fuel System Diagnosis |
| 8 | Inspect for the following conditions: Collapsed air intake duct Restricted air filter element-Refer to Air Cleaner Assembly Replacement . Contaminated fuel-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Spark plugs for being fouled-Refer to Spark Plug Inspection . If the spark plugs are fouled, determine what caused the condition. Engine mechanical condition, for example, broken timing chain, low compression-Refer to Engine Compression Test in Engine Mechanical. Restricted exhaust system-Refer to Restricted Exhaust in Engine Exhaust An engine coolant temperature (ECT) sensor that has shifted in value-Refer to Temperature vs Resistance . Compare the MAP parameter to another vehicle. The parameters should be close in value. Refer to DTC P0106 . Did you complete the action? | Go to Step 9 | ||
| 9 | With a scan tool, clear the DTCs. Attempt to start the engine. Does the engine start and continue to operate? | Go to Step 10 | Go to Step 2 | |
| 10 | Idle the engine. Allow the engine to reach operating temperature. Observe the DTC information with a scan tool. Are any DTCs displayed? | Go to Diagnostic Trouble Code (DTC) List | System OK | |
| IMPORTANT |
|---|
| You may need to command the fuel pump ON a few times in order to obtain the highest possible fuel pressure. |
Engine Cranks but Does Not Run
Circuit Description
The main relay is a normally open relay. The relay armature is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the armature contact at all times. The powertrain control module (PCM) supplies the ground path to the relay coil control circuit, via an internal integrated circuit called an output driver module (ODM). When the PCM commands the relay ON, the relay coil creates an electromagnetic field. This electromagnetic field overcomes the spring tension and pulls the armature contact into the stationary contact of the relay load circuit. The closing of the relay contacts allows current to flow from the battery to the following fuses and relays
- TOS fuse
- PCM fuse
- ODD INJ/Coil fuse
- Pre 02/CAM fuse
- Post 02 fuse
- Even INJ/Coil fuse
- Low speed fan relay
- S/P fan relay
When the ignition switch is turned to the OFF position, the main relay will continue to be energized for 20 seconds. Once the power is interrupted to the output driver module in the PCM, the relay electromagnetic field collapses. This allows the spring tension to separate the relay armature contact from the relay load circuit contact, which interrupts current flow to the fuses.
If the main relay fails to close the engine will crank, but will not run. The PCM class 2 communications will be available with the use of a scan tool.
The main relay system diagnosis table assumes that the vehicle battery if fully charged. Refer to Battery Inspection/Test in Engine Electrical.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Power Distribution Schematics in Wiring Systems and Engine Controls Schematics Connector End View References: Power and Grounding Connector End Views , Electrical Center Identification Views in Wiring Systems, and Powertrain Control Module (PCM) Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls | |
| 2 | Turn ON the ignition, with the engine OFF. Remove the underhood fuse block cover. Probe the following fuses with a test lamp that is connected to a good ground: TOS fuse PCM fuse Odd INJ/Coil fuse Pre 02/CAM fuse Post 02 fuse Even INJ/Coil fuse Refer to Troubleshooting with a Test Lamp in Wiring Systems.Does the test lamp illuminate on at least one test point of each fuse? | Go to Step 3 | Go to Step 17 | |
| 3 | Turn OFF the ignition. Probe both test points of the PCM fuse in the underhood fuse block with a test lamp that is connected to a good ground. Does the test lamp illuminate on either test point of the fuse? | Go to Step 4 | Go to Step 47 | |
| 4 | Turn OFF the ignition. Remove the main relay from the underhood fuse block with the J 43244 . Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Probe both the test points of the PCM fuse with a test lamp that is connected to a good ground. Does the test lamp illuminate on either test point of the fuse? | Go to Step 5 | Go to Step 14 | |
| 5 | Turn OFF the ignition. Remove the TOS fuse from the underhood fuse block. Probe both test points of the PCM fuse with a test lamp that is connected to a good ground. Does the test lamp illuminate on either test point of the fuse? | Go to Step 6 | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | |
| 6 | Turn OFF the ignition. Remove the Odd INJ/Coil fuse from the underhood fuse block. Probe both test points of the PCM fuse with a test lamp that is connected to a good ground. Does the test lamp illuminate on either test point of the fuse? | Go to Step 7 | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | |
| 7 | Turn OFF the ignition. Remove the Pre O2/CAM fuse from the underhood fuse block. Probe both test points of the PCM fuse with a test lamp that is connected to a good ground. Does the test lamp illuminate on either test point of the fuse? | Go to Step 8 | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | |
| 8 | Turn OFF the ignition. Remove the Post O2 fuse from the underhood fuse block. Probe both test points of the PCM fuse with a test lamp that is connected to a good ground. Does the test lamp illuminate on either test point of the fuse? | Go to Step 9 | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | |
| 9 | Turn OFF the ignition. Remove the Even INJ/Coil fuse from the underhood fuse block. Probe both test points of the PCM fuse with a test lamp that is connected to a good ground. Does the test lamp illuminate on either test point of the fuse? | Go to Step 10 | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | |
| 10 | Turn OFF the ignition. Remove the low speed fan relay from the underhood fuse block with the J 43244 Relay Puller Pliers. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Probe both test points of the PCM fuse with a test lamp that is connected to a good ground. Does the test lamp illuminate on either test point of the fuse? | Go to Step 11 | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | |
| 11 | Turn OFF the ignition. Remove the high speed fan relay from the underhood fuse block. Probe both test points of the PCM fuse with a test lamp that is connected to a good ground. Does the test lamp illuminate on either test point of the fuse? | Go to Step 12 | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | |
| 12 | Turn OFF the ignition. Remove the S/P fan relay from the underhood fuse block. Probe both test points of the PCM fuse with a test lamp that is connected to a good ground. Does the test lamp illuminate on either test point of the fuse? | Go to Step 13 | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | |
| 13 | Turn OFF the ignition. Remove the PCM fuse from the underhood fuse block. NOTE: Refer to Test Probe Notice in Cautions and Notices. Probe the main relay load circuit bus bar terminal in the underhood fuse block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate? | Go to Step 41 | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | |
| 14 | Turn OFF the ignition. NOTE: Refer to Test Probe Notice in Cautions and Notices. Probe the main relay coil control circuit terminal in the underhood fuse block with a test lamp that is connected to battery positive voltage. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate? | Go to Step 15 | Go to Step 30 | |
| 15 | Turn OFF the ignition. Disconnect the powertrain control module (PCM) electrical connector that contains the relay coil control circuit. Refer to Powertrain Control Module (PCM) Replacement . Probe the main relay coil control circuit terminal in the underhood fuse block with a test lamp this is connected to battery positive voltage. Does the test lamp illuminate? | Go to Step 16 | Go to Step 37 | |
| 16 | Turn OFF the ignition. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical. Disconnect the underhood fuse block electrical connector that contains the main relay coil control circuit. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Probe the main relay coil control circuit at the underhood fuse block electrical connector with a test lamp that is connected to battery positive voltage. Does the test lamp illuminate? | Go to Step 38 | Go to Step 41 | |
| 17 | Turn OFF the ignition. Remove the main relay from the underhood fuse block with the J 43244 . Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. NOTE: Refer to Test Probe Notice in Cautions and Notices. Probe the battery positive voltage terminal for the relay coil in the underhood fuse block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate? | Go to Step 19 | Go to Step 18 | |
| 18 | Probe the mounting stud for the positive battery cable at the underhood fuse block with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 41 | Go to Diagnostic System Check - Engine Electrical in Engine Electrical | |
| 19 | Turn OFF the ignition. Probe the relay coil control circuit terminal in the underhood fuse block with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 23 | Go to Step 20 | |
| 20 | Turn ON the ignition, with the engine OFF. Probe the relay coil control circuit terminal in the underhood fuse block with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 21 | Go to Step 25 | |
| 21 | Turn OFF the ignition. Disconnect the PCM electrical connector that contains the relay coil control circuit. Refer to Powertrain Control Module (PCM) Replacement . Turn ON the ignition, with the engine OFF. Probe the main relay coil control circuit at the underhood fuse block with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 22 | Go to Step 37 | |
| 22 | Turn OFF the ignition. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical. Disconnect the underhood fuse block electrical connector that contains the main relay coil control circuit. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Disconnect the main relay coil connector circuit terminal from the underhood fuse block electrical connector. Refer to Pull to Seat Connectors in Wiring Systems. Connect the electrical connector that contains the main relay coil control circuit to the underhood fuse block. Connect the negative battery cable at the battery. Turn ON the ignition, with the engine OFF. Probe the main relay coil control circuit terminal at the underhood fuse block electrical connector with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 39 | Go to Step 41 | |
| 23 | Turn OFF the ignition. Disconnect the PCM electrical connector that contains the relay coil control circuit. Refer to Powertrain Control Module (PCM) Replacement . Probe the main relay coil control circuit terminal in the underhood fuse block with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 24 | Go to Step 37 | |
| 24 | Turn OFF the ignition. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical. Disconnect the underhood fuse block electrical connector that contains the main relay coil control circuit. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Connect the negative battery cable at the battery. Probe the main relay coil connector circuit at the underhood fuse block electrical connector with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 39 | Go to Step 41 | |
| 25 | Turn OFF the ignition. Probe the battery positive voltage terminal for the main relay armature at the underhood fuse block with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 26 | Go to Step 41 | |
| 26 | Turn ON the ignition, with the engine OFF. NOTE: Refer to Test Probe Notice in Cautions and Notices. Probe the relay coil control circuit terminal at the underhood fuse block with a test lamp that is connected to battery positive voltage. Does the test lamp illuminate? | Go to Step 29 | Go to Step 27 | |
| 27 | Turn OFF the ignition. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical. Disconnect the underhood fuse block electrical connector that contains the main relay coil control circuit. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Disconnect the PCM electrical connector that contains the main relay coil control circuit. Refer to Powertrain Control Module (PCM) Replacement . Measure the resistance of the relay coil control circuit from the underhood fuse block electrical connector to the PCM electrical connector with a DMM. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems. Does the resistance measure greater than the specified value? | 5 ohm | Go to Step 40 | Go to Step 28 |
| 28 | Test the main relay coil control bus bar circuit of the underhood fuse block for a high resistance or an open. Refer to Circuit Testing in Wiring Systems. Did you find a condition? | Go to Step 41 | Go to Step 37 | |
| 29 | Turn OFF the ignition. Connect a 20-amp fused jumper wire between the battery positive voltage circuit terminal of the underhood fuse block and the relay load circuit terminal of the underhood fuse block. Refer to Using Fused Jumper Wires in Wiring Systems. Probe the following fuses with a test lamp that is connected to a good ground: The TOS fuse The PCM fuse The Odd INJ/Coil fuse The Pre O2/CAM fuse The Post O2 fuse The Even INJ/Coil fuse Does the test lamp illuminate on at least one test point of each fuse? | Go to Step 30 | Go to Step 41 | |
| 30 | Measure the resistance from terminal #85 of the relay to terminal #86 with a DMM. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems. Does the resistance measure within the specified range? | 70-110 ohm | Go to Step 31 | Go to Step 42 |
| 31 | Measure the resistance from terminal #30 of the relay to terminal #87 with a DMM. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems. Does the DMM display the specified value? | Infinity ohm | Go to Step 32 | Go to Step 42 |
| 32 | Measure the resistance from terminal #30 of the relay to terminal #85 with a DMM. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems. Does the DMM display the specified value? | Infinity ohm | Go to Step 33 | Go to Step 42 |
| 33 | Measure the resistance from terminal #85 of the relay to terminal #87 with a DMM. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems. Does the DMM display the specified value? | Infinity ohm | Go to Step 34 | Go to Step 42 |
| 34 | Measure the resistance from terminal #86 of the relay to terminal #87 with a DMM. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems. Does the DMM display the specified value? | Infinity ohm | Go to Step 35 | Go to Step 42 |
| 35 | Connect a 20-amp fused jumper wire from the battery positive cable at the battery to relay terminal #85. Refer to Using Fused Jumper Wires in Wiring Systems. Connect a jumper wire from the negative battery cable to the relay terminal #86. Measure the resistance from terminal #30 of the relay to terminal #87 with a DMM. Does the resistance measure more than the specified value? | 3 ohm | Go to Step 42 | Go to Step 36 |
| 36 | Test for an intermittent and for a poor connection at the main relay location on the underhood fuse block. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find a condition? | Go to Step 41 | Go to Intermittent Conditions | |
| 37 | Test for shorted terminals and poor connections at the PCM electrical connector. Refer to Testing for Intermittent Conditions and Poor Connections and Micro-Pack 100W Connectors in Wiring Systems. Did you find and correct the condition? | Go to Step 47 | Go to Step 46 | |
| 38 | Repair the short to ground in the relay coil control circuit between the underhood fuse block and the PCM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 47 | ||
| 39 | Repair the short to voltage in the relay coil control circuit between the underhood fuse block and the PCM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 47 | ||
| 40 | Repair the high resistance or an open in the relay coil control circuit between the underhood fuse block and the PCM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 47 | ||
| 41 | Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 47 | ||
| 42 | Replace the main relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Did you complete the replacement? | Go to Step 47 | ||
| 43 | Replace the low speed fan relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Did you complete the replacement? | Go to Step 47 | ||
| 44 | Replace the high speed fan relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Did you complete the replacement? | Go to Step 47 | ||
| 45 | Replace the S/P fan relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Did you complete the replacement? | Go to Step 47 | ||
| 46 | Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement . Did you complete the replacement? | Go to Step 47 | ||
| 47 | Reassemble the vehicle as necessary. Replace any open fuses. Clear any DTCs with a scan tool. Start the engine. Operate the vehicle in order to verify the repair. Did you correct the condition? | Go to Step 48 | Go to Engine Cranks but Does Not Run | |
| 48 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List | System OK | |
| NOTE |
|---|
| Refer to Test Probe Notice in Cautions and Notices. |
| NOTE |
|---|
| Refer to Test Probe Notice in Cautions and Notices. |
| NOTE |
|---|
| Refer to Test Probe Notice in Cautions and Notices. |
| NOTE |
|---|
| Refer to Test Probe Notice in Cautions and Notices. |
Main Relay Circuit Diagnosis
When the ignition switch is turned ON, the control module energizes the fuel pump relay which applies power to the in-tank fuel pump. The fuel pump relay will remain on as long as the engine is running or cranking and the control module is receiving reference pulses. If no reference pulses are present, the control module de-energizes the fuel pump relay within 2 seconds after the ignition is turned ON or the engine is stopped.
Diagnostic Aids
Listen for an audible hiss from the fuel pump when the fuel pump relay is commanded ON. A vibration in the fuel feed line when the fuel pump relay is commanded ON indicates that the fuel pump is operating.
For an intermittent condition, refer to Intermittent Conditions .
Test Description
The numbers below refer to the step numbers on the diagnostic table
- 2: This step verifies that the fuel pump operates.
- 3: This step determines if the condition is located on the coil side or the switch side of the circuit.
- 7: This step tests for a grounded voltage supply circuit.
- 9: This step verifies that the fuel pump fuse is providing voltage to the fuel pump relay.
- 15: This step tests for an intermittent condition between the fuse and the fuel pump.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics | |||
| 1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls |
| 2 | Turn ON the ignition, with the engine OFF. Command the fuel pump relay ON and OFF with a scan tool. Does the fuel pump turn ON and OFF? | Go to Diagnostic Aids | Go to Step 3 |
| 3 | Command the fuel pump relay ON and OFF with a scan tool. Do you hear a click when you command the fuel pump relay ON and OFF? | Go to Step 4 | Go to Step 16 |
| 4 | Turn ON the ignition, with the engine OFF. Does the fuel pump operate continuously? | Go to Step 5 | Go to Step 6 |
| 5 | Turn OFF the ignition. Disconnect the fuel pump relay. Turn ON the ignition, with the engine OFF. Does the fuel pump operate continuously? | Go to Step 17 | Go to Step 20 |
| 6 | Is the fuel pump fuse open? | Go to Step 7 | Go to Step 9 |
| 7 | Disconnect the fuel pump harness in-line connector located near the fuel tank. Refer to Power and Grounding Component Views in Wiring Systems. Test the supply voltage circuit of the fuel pump for a grounded circuit. Refer to Wiring Repairs and Connector Repairs in Wiring Systems. Replace the fuel pump fuse, if necessary. Did you find and correct the condition? | Go to Step 21 | Go to Step 8 |
| 8 | Lower the fuel tank, if necessary. Refer to Fuel Tank Replacement . Test or inspect the fuel tank electrical harness for the following conditions: Damage to the harness A short to ground-Refer to Wiring Repairs and Connector Repairs in Wiring Systems. Replace the fuel pump fuse, if necessary. Did you find and correct the condition? | Go to Step 21 | Go to Step 15 |
| 9 | Turn OFF the ignition. Disconnect the fuel pump relay. Probe the battery positive voltage circuit of the fuel pump relay with a test lamp connected to a good ground. Does the test lamp illuminate? | Go to Step 10 | Go to Step 18 |
| 10 | Connect a 15-amp fused jumper wire between the battery positive voltage circuit and the fuel pump supply circuit of the fuel pump relay. Does the fuel pump operate? | Go to Step 16 | Go to Step 11 |
| 11 | Disconnect the fuel pump harness in-line connector located near the fuel tank. Refer to Power and Grounding Component Views in Wiring Systems. Test the supply voltage circuit of the fuel pump for an open or for high resistance between the fuel pump relay and the in-line connector. Refer to Wiring Repairs and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 22 | Go to Step 12 |
| 12 | Test the ground circuit of the fuel pump for an open or for high resistance. Refer to Wiring Repairs and Connector Repairs in Wiring Systems Did you find and correct the condition? | Go to Step 22 | Go to Step 13 |
| 13 | Inspect for poor connections at the fuel pump in-line connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 22 | Go to Step 14 |
| 14 | Lower the fuel tank. Refer to Fuel Tank Replacement . Test or inspect the fuel tank electrical harness for the following conditions: Damage to the harness An open circuit-Refer to Wiring Repairs and Connector Repairs in Wiring Systems Did you find and correct the condition? | Go to Step 22 | Go to Step 20 |
| 15 | Connect all disconnected components. Install a new fuel pump fuse. Command the fuel pump ON with a scan tool. Inspect the fuel pump fuse. Is the fuel pump fuse open? | Go to Step 20 | Go to Diagnostic Aids |
| 16 | Inspect for poor connections at the fuel pump relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 22 | Go to Step 21 |
| 17 | Repair the supply voltage circuit of the fuel pump for a short to voltage. Refer to Wiring Repairs and Connector Repairs in Wiring Systems. Did you complete the repair? | Go to Step 22 | |
| 18 | Repair the battery positive voltage circuit of the fuel pump relay for an open. Refer to Wiring Repairs and Connector Repairs in Wiring Systems Did you complete the repair? | Go to Step 22 | |
| 19 | Test for an intermittent and for a poor connection at the fuel pump connector within the fuel tank. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 22 | Go to Step 20 |
| 20 | Replace the fuel tank module. Refer to Fuel Tank Module Replacement - Primary . Replace the fuel pump fuse, if necessary. Did you complete the replacement? | Go to Step 22 | |
| 21 | Replace the fuel pump relay. Did you complete the replacement? | Go to Step 22 | |
| 22 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |
Fuel Pump Electrical Circuit Diagnosis
System Description
When you turn the ignition switch to the ON position, the control module enables the fuel pump relay, which in turn powers the fuel pump. The fuel pump remains ON as long as the engine is cranking or running and the control module receives ignition reference pulses. If there are no ignition reference pulses, the control module shuts the fuel pump OFF within 2 seconds after the ignition was switched to the ON position, or if the engine stops.
The fuel tank stores the fuel supply. The fuel pump is an electric pump that is attached to the primary fuel tank module assembly. The fuel pump also supplies fuel to the siphon jet pump, also attached to the primary fuel tank module. The siphon jet pump draws fuel from the secondary side of the fuel tank to the primary side of the fuel tank. The fuel pump is designed to provide fuel at a pressure above the pressure that is needed by the fuel injectors. A fuel pressure regulator, which is also located in the fuel tank, is attached to the primary fuel tank module. The fuel pressure regulator keeps the fuel available to the fuel injectors at a regulated pressure. The port on the fuel pressure regulator is an atmospheric vent. The fuel pressure regulator does not compensate for changes in intake manifold vacuum. Unused fuel is returned from the fuel filter to the fuel tank by a separate fuel return pipe.
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step verifies that the fuel pump is operating.
- 4: This step verifies that the vehicle is not out of fuel. If the right fuel sender is below 0.8 volt, and the left fuel sender is above 0.8 volt, a fuel transfer condition exists.
- 7: This step tests for an internal fuel leak. If the fuel pressure drops during this test, then an internal loss of pressure is indicated.
- 10: This step isolates the condition. Replace the primary fuel tank module assembly, if the fuel pressure remains constant, after closing the valve on the fuel pipe shut-off adapter. Locate and replace the leaking fuel injector if the pressure continues to decrease after closing the valve on the adapter.
- 13: This step isolates the condition. Replace the primary fuel tank module assembly for a stuck open or leaking fuel pressure regulator, if the fuel pressure increases above the specified value.
- 16: This step verifies that a circuit condition is not the cause of a fuel pressure concern. Inspect all fuel pump electrical circuits thoroughly.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Fuel Hose/Pipes Routing Diagram | ||||
| 1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls | |
| 2 | IMPORTANT: Inspect the fuel system for the following conditions before proceeding with this diagnostic procedure: Damage to the fuel system External fuel leaks Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Does the fuel pump operate? | Go to Step 3 | Go to Fuel Pump Electrical Circuit Diagnosis | |
| 3 | Observe the fuel level sensor left voltage with a scan tool. Is the fuel level sensor left voltage less than the specified value? | 0.8 V | Go to Step 4 | Go to Step 6 |
| 4 | Observe the fuel level sensor right voltage with a scan tool. Is the fuel level sensor right voltage less than the specified value? | 0.8 V | Go to Step 5 | Go to Step 14 |
| 5 | Add the specified amount of fuel. Operate the vehicle within the conditions of the customer's concern. Monitor the fuel trim related parameters with a scan tool. Refer to Scan Tool Data List . Do any of the scan tool parameters indicate a lean condition? | 19 L (5 gal) | Go to Step 15 | Go to Symptoms - Engine Controls |
| 6 | Turn OFF the ignition. Install the fuel pressure gage. Refer to Fuel Pressure Gage Installation and Removal . Turn ON the ignition, with the engine OFF. IMPORTANT: The fuel pump may need to be commanded ON a few times in order to obtain the highest possible fuel pressure. DO NOT start the engine. Command the fuel pump ON with a scan tool. Observe the fuel pressure gage while the fuel pump is operating. Is the fuel pressure within the specified range? | 380-427 kPa (55-62 psi) | Go to Step 7 | Go to Step 11 |
| 7 | IMPORTANT: The fuel pressure will drop when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. Allow the fuel pressure to stabilize. Monitor the fuel pressure gage for 1 minute. Does the fuel pressure decrease by more than the specified value? | 34 kPa (5 psi) | Go to Step 10 | Go to Step 8 |
| 8 | Relieve the fuel pressure to the first specified value. Monitor the fuel pressure gage for 5 minutes. Does the fuel pressure decrease by more than the second specified value? | 69 kPa (10 psi) 14 kPa (2 psi) | Go to Step 19 | Go to Step 9 |
| 9 | Operate the vehicle within the conditions of the customer's concern. Monitor the fuel related parameters with a scan tool. Do any of the scan tool parameters indicate a lean condition? | Go to Step 15 | Go to Symptoms - Engine Controls | |
| 10 | Turn OFF the ignition. Relieve the fuel pressure. Refer to Fuel Pressure Relief Procedure . Disconnect the fuel feed pipe from the fuel rail. Refer to Quick Connect Fitting(s) Service (Metal Collar) . Install the appropriate J 37287 Fuel Line Shut-Off Adapters between the fuel feed pipe and the fuel rail inlet. Open the valve on the fuel feed pipe shut-off adapter. Command the fuel pump ON with a scan tool. Bleed the air from the fuel system. Close the fuel pipe shut-off valve. Monitor the fuel pressure gage for 1 minute. Does the fuel pressure remain constant? | Go to Step 19 | Go to Step 18 | |
| 11 | Is the fuel pressure more than the specified value? | 410 kPa (60 psi) | Go to Step 12 | Go to Step 13 |
| 12 | Inspect the fuel return hose/pipe for a restriction. Did you find and correct the condition? | Go to Step 20 | Go to Step 19 | |
| 13 | Turn OFF the ignition. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedure . Disconnect the fuel return hose from the fuel return outlet of the fuel filter. Refer to Quick Connect Fitting(s) Service (Metal Collar) . Install the appropriate J 37287 between the return outlet of the fuel filter and the fuel return hose. Open the valve in the fuel pipe shut-off adapter. Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Bleed the air from the fuel system. Monitor the fuel pressure gage. Slowly close the valve in the fuel pipe shut-off adapter. Command the fuel pump ON with a scan tool. Does the fuel pressure increase to more than the specified value? | 380-427 kPa (55-62 psi) | Go to Step 19 | Go to Step 15 |
| 14 | Remove both fuel tank modules. Refer to Fuel Tank Module Replacement - Primary and Fuel Tank Module Replacement - Secondary . Inspect the feed fuel pipe of the siphon jet pump for a restriction. Inspect the fuel strainer for contaminants. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Did you find and correct the condition? | Go to Step 20 | Go to Step 19 | |
| 15 | Inspect the following components for a restriction: The fuel filter The fuel feed pipe Did you find and correct the condition? | Go to Step 20 | Go to Step 16 | |
| 16 | Inspect the harness connectors and ground circuits of the fuel pump for poor connections. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 17 | |
| 17 | Remove the primary fuel tank module. Refer to Fuel Tank Module Replacement - Primary . Inspect the following items: The fuel pump flex hose for damage The in-tank fuel pump harness connectors for poor connections The fuel strainer for a restriction For contaminates in the fuel tank Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Did you find and correct the condition? | Go to Step 20 | Go to Step 19 | |
| 18 | Turn OFF the ignition. Raise the fuel rail, with the fuel lines connected. Refer to Fuel Injector Replacement and Fuel Rail Assembly Replacement . Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Locate and replace the leaking fuel injector. Refer to Fuel Injector Replacement and Fuel Rail Assembly Replacement . Did you complete the replacement? | Go to Step 20 | ||
| 19 | Replace the primary fuel tank module. Refer to Fuel Tank Module Replacement - Primary . Did you complete the replacement? | Go to Step 20 | ||
| 20 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 | |
| IMPORTANT |
|---|
| Inspect the fuel system for the following conditions before proceeding with this diagnostic procedure: Damage to the fuel system External fuel leaks |
| IMPORTANT |
|---|
| The fuel pump may need to be commanded ON a few times in order to obtain the highest possible fuel pressure. DO NOT start the engine. |
| IMPORTANT |
|---|
| The fuel pressure will drop when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. |
Fuel System Diagnosis
The control module enables the appropriate fuel injector pulse for each cylinder. Ignition voltage is supplied directly to the fuel injectors. The control module controls each fuel injector by grounding the control circuit via a solid state device called a driver. A fuel injector coil winding resistance that is too high or too low will affect engine driveability. A fuel injector control circuit DTC may not set, but a misfire may be apparent. The fuel injector coil windings are affected by temperature. The resistance of the fuel injector coil windings will increase as the temperature of the fuel injector increases.
- The use of Dielectric compound GM P/N 12377900 (Canadian P/N 10953529) in the fuel injector electrical connector may eliminate a corrosion condition.
- Monitoring the misfire current counters, or misfire graph, may help isolate the fuel injector that is causing the condition.
- Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition.
- Perform the fuel injector coil test within the conditions of the customers concern. A fuel injector condition may only be apparent at a certain temperature, or under certain conditions.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls | |
| 2 | Observe the ECT sensor parameter with a scan tool. Is the ECT sensor parameter within the specified range? | 10-32°C (50-90°F) | Go to Step 3 | Go to Step 4 |
| 3 | Measure the resistance of each fuel injector with a DMM. Refer to Testing for Continuity in Wiring Systems. Do any of the fuel injectors display a resistance outside the specified range? | 11-14 ohm | Go to Step 6 | Go to Diagnostic Aids |
| 4 | Measure the resistance of each fuel injector with a DMM. Refer to Testing for Continuity in Wiring Systems. Record each fuel injector value. Subtract the lowest resistance value from the highest resistance value. Is the difference equal to, or less than, the specified value? | 3 ohm | Go to Fuel Injector Balance Test with Special Tool or Fuel Injector Balance Test with Tech 2 | Go to Step 5 |
| 5 | Add all of the fuel injector resistance values, to obtain a total resistance value. Divide the total resistance value by the number of fuel injectors, to obtain an average resistance value. Subtract the lowest individual fuel injector resistance value from the average resistance value. Compute the difference between the highest individual fuel injector resistance value and the average resistance value. Replace the fuel injector that displays the greatest resistance difference, above or below the average. Refer to Fuel Injector Replacement . Did you complete the replacement? | Go to Step 7 | ||
| 6 | Replace the fuel injector or fuel injectors with resistance that is out of the specified range. Refer to Fuel Injector Replacement . Did you complete the replacement? | 11-14 ohm | Go to Step 7 | |
| 7 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 | |
Fuel Injector Coil Test
The scan tool is first used to energize the fuel pump. The fuel injector tester is then used to pulse each injector for a precise amount of time, allowing fuel into the manifold. This causes a drop in system fuel pressure that can be recorded and used to compare each injector.
| Cylinder | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| 1st Reading | 296 kPa (43 psi) | 296 kPa (43 psi) | 296 kPa (43 psi) | 296 kPa (43 psi) |
| 2nd Reading | 131 kPa (19 psi) | 117 kPa (17 psi) | 124 kPa (18 psi) | 145 kPa (21 psi) |
| Amount of Drop | 165 kPa (24 psi) | 179 kPa (26 psi) | 172 kPa (25 psi) | 151 kPa (22 psi) |
| Average Range: 156-176 kPa (22.5-25.5 psi) | Injector OK | Replace fuel injector - too much fuel pressure drop | Injector OK | Replace fuel injector - too little fuel pressure drop |
Fuel Injector Balance Test Example (Typical)
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls | |
| 2 | Did you perform the Fuel Injector Coil Test? | Go to Step 3 | Go to Fuel Injector Coil Test | |
| 3 | IMPORTANT: DO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F). IMPORTANT: Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic. Install the fuel pressure gage. Refer to Fuel Pressure Gage Installation and Removal . Turn ON the ignition, with the engine OFF. IMPORTANT: The fuel pump relay may need to be commanded ON a few times, in order to obtain the highest possible fuel pressure. Command the fuel pump relay ON with a scan tool. Observe the fuel pressure gage, with the fuel pump operating. Is the fuel pressure within the specified range? | 384-425 kPa (56-62 psi) | Go to Step 4 | Go to Fuel System Diagnosis |
| 4 | IMPORTANT: The fuel pressure will decrease when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. Monitor the fuel pressure gage for 5 minutes.Does the fuel pressure decrease to less than the specified value? | 34 kPa (5 psi) | Go to Fuel System Diagnosis | Go to Step 5 |
| 5 | NOTE: Do Not repeat any portion of this test before running the engine in order to prevent the engine from flooding. Connect the J 39021 Fuel Injector Tester to a fuel injector. Set the amperage supply selector switch on the fuel injector tester to the Balance Test 0.5-2.5 amp position. Command the fuel pump relay ON and OFF with a scan tool. Record the fuel pressure indicated by the fuel pressure gage after the fuel pressure stabilizes. This is the first pressure reading. IMPORTANT: Record the fuel pressure value immediately after the fuel injector stops pulsing. The fuel pressure may rise after the fuel injector stops pulsing. Do not record the higher fuel pressure value. Energize the fuel injector by depressing the Push to Start Test button on the fuel injector tester. Record the fuel pressure indicated by the fuel pressure gage after the fuel injector has stopped pulsing. This is the second fuel pressure reading. Repeat steps 1 through 6 for each fuel injector. Subtract the second pressure reading from the first pressure reading for one fuel injector. The result is the pressure drop value. Obtain a pressure drop value for each fuel injector. Add all of the individual pressure drop values. This is the total pressure drop. Divide the total pressure drop by the number of fuel injectors. This is the average pressure drop. Is the difference between any individual pressure drop and the average pressure drop more than the specified value? | 10 kPa (1.5 psi) | Go to Step 6 | Go to Symptoms - Engine Controls |
| 6 | Perform the Fuel Injector Cleaning Procedure . Did you complete the procedure? | Go to Step 7 | ||
| 7 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Symptoms - Engine Controls |
| IMPORTANT |
|---|
| DO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F). |
| IMPORTANT |
|---|
| Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic. |
| IMPORTANT |
|---|
| The fuel pump relay may need to be commanded ON a few times, in order to obtain the highest possible fuel pressure. |
| IMPORTANT |
|---|
| The fuel pressure will decrease when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. |
| NOTE |
|---|
| Do Not repeat any portion of this test before running the engine in order to prevent the engine from flooding. |
| IMPORTANT |
|---|
| Record the fuel pressure value immediately after the fuel injector stops pulsing. The fuel pressure may rise after the fuel injector stops pulsing. Do not record the higher fuel pressure value. |
Fuel Injector Balance Test with Special Tool
The scan tool is first used to energize the fuel pump. The scan tool is then used to pulse each injector for a precise amount of time, allowing fuel into the manifold. This causes a drop in system fuel pressure that can be recorded and used to compare the flow through each injector.
| Cylinder | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| 1st Reading | 296 kPa (43 psi) | 296 kPa (43 psi) | 296 kPa (43 psi) | 296 kPa (43 psi) |
| 2nd Reading | 131 kPa (19 psi) | 117 kPa (17 psi) | 124 kPa (18 psi) | 145 kPa (21 psi) |
| Amount of Drop | 165 kPa (24 psi) | 179 kPa (26 psi) | 172 kPa (25 psi) | 151 kPa (22 psi) |
| Average Range: 156-176 kPa (22.5-25.5 psi) | Injector OK | Replace fuel injector - too much fuel pressure drop | Injector OK | Replace fuel injector - too little fuel pressure drop |
Fuel Injector Balance Test Example (Typical)
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls | |
| 2 | Did you perform the Fuel Injector Coil Test? | Go to Step 3 | Go to Fuel Injector Coil Test | |
| 3 | IMPORTANT: DO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F). IMPORTANT: Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic. Install the fuel pressure gage. Refer to Fuel Pressure Gage Installation and Removal . Turn ON the ignition, with the engine OFF. IMPORTANT: The fuel pump relay may need to be commanded ON a few times in order to obtain the highest possible fuel pressure. Command the fuel pump relay ON with a scan tool. Observe the fuel pressure gage, with the fuel pump operating. Is the fuel pressure within the specified value? | 382-425 kPa (56-62 psi) | Go to Step 4 | Go to Fuel System Diagnosis |
| 4 | IMPORTANT: The fuel pressure will decrease when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. Monitor the fuel pressure gage for 5 minutes.Does the fuel pressure decrease to less than the specified value? | 34 kPa (5 psi) | Go to Fuel System Diagnosis | Go to Step 5 |
| 5 | NOTE: Do Not repeat any portion of this test before running the engine in order to prevent the engine from flooding. Select the Fuel Injector Balance Test function with a scan tool. Select an injector to be tested. Press Enter. This will prime the fuel system. Record the fuel pressure indicated by the fuel pressure gage after the fuel pressure stabilizes. This is the 1st pressure reading. IMPORTANT: Record the fuel pressure value immediately after the fuel injector stops pulsing. The fuel pressure may rise after the fuel injector stops pulsing. Do not record the higher fuel pressure value. Energize the fuel injector by depressing the Pulse Injector button on the scan tool. This will energize the injector and decrease the fuel pressure. Record the fuel pressure indicated by the fuel pressure gage after the fuel injector has stopped pulsing. This is the 2nd pressure reading. Press Enter again to bring you back to the Select Injector screen. Repeat for each fuel injector. Subtract the 2nd pressure reading from the 1st pressure reading for one fuel injector. The result is the pressure drop value. Obtain a pressure drop value for each fuel injector. Add all of the individual pressure drop values. This is the total pressure drop. Divide the total pressure drop by the number of fuel injectors. This is the average pressure drop. Is the difference between any individual pressure drop and the average pressure drop more than the specified value? | 10 kPa (1.5 psi) | Go to Step 6 | Go to Symptoms - Engine Controls |
| 6 | Perform the Fuel Injector Cleaning Procedure . Did you complete the procedure? | Go to Step 7 | ||
| 7 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Symptoms - Engine Controls |
| IMPORTANT |
|---|
| DO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F). |
| IMPORTANT |
|---|
| Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic. |
| IMPORTANT |
|---|
| The fuel pump relay may need to be commanded ON a few times in order to obtain the highest possible fuel pressure. |
| IMPORTANT |
|---|
| The fuel pressure will decrease when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. |
| NOTE |
|---|
| Do Not repeat any portion of this test before running the engine in order to prevent the engine from flooding. |
| IMPORTANT |
|---|
| Record the fuel pressure value immediately after the fuel injector stops pulsing. The fuel pressure may rise after the fuel injector stops pulsing. Do not record the higher fuel pressure value. |
Fuel Injector Balance Test with Tech 2
The fuel tank leak test is used to locate any fuel or fuel vapor escaping the fuel tank area. Fuel vapors escaping above the fuel level will be detected when the EVAP leak diagnostic completes one test cycle. the MIL will illuminate after the EVAP leak diagnostic completes two test cycles only when a condition is detected.
- Operate the vehicle under the condition of the customers concern. Under high temperature conditions fuel vapors may increase to the point of EVAP canister vapor saturation. Fuel vapors would then be released into the atmosphere. Once the engine is running and EVAP purge is enabled, all fuel vapor release would be eliminated.
- Movement of the EVAP pipes or fuel pipes may help find an intermittent condition.
- 3: This step tests for location of fuel leakage in the fuel lines.
- 4: This step tests for fuel leaks below the fuel level in the fuel tank.
- 5: This step tests for a location of fuel vapors escaping above the fuel level in the fuel tank.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls |
| 2 | CAUTION: Refer to Gasoline/Gasoline Vapors Caution in Cautions and Notices. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. Inspect the fuel tanks for damage or external leaks. Did you find fuel leaking from the fuel tank? | Go to Step 7 | Go to Step 3 |
| 3 | Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Inspect for fuel leaking from the fuel pipe. Did you locate a fuel leak from the fuel pipe? | Go to Step 8 | Go to Step 4 |
| 4 | Install the J 41415-40 Fuel Tank Cap Adapter. Connect the J 41413-200 Evaporative Emissions System Tester to the J 41415-40 . Command the EVAP vent valve ON with a scan tool. Pressurize the fuel tank with the J 41413-200 . Inspect for a fuel leak from the fuel tank. Did you locate a fuel leak from the fuel tank? | Go to Step 7 | Go to Step 5 |
| 5 | Turn the Nitrogen/Smoke valve on the J 41413-200 control panel to SMOKE. Use the remote switch to introduce smoke into the sealed system. Inspect the entire system with the with the J 41413-SPT High Intensity White Light for exiting smoke. Did you locate a leak source? | Go to Step 6 | Go to Diagnostic Aids |
| 6 | Repair the system as necessary. Did you complete the repair? | System OK | |
| 7 | Replace the fuel tank. Refer to Fuel Tank Replacement . Did you complete the repair? | System OK | |
| 8 | Replace the leaking fuel pipe. Refer to Fuel Hose/Pipes Replacement - Chassis and Fuel Hose/Pipes Replacement - Engine Compartment . Did you complete the replacement? | System OK |
| CAUTION |
|---|
| Refer to Gasoline/Gasoline Vapors Caution in Cautions and Notices. |
Fuel Tank Leak Test
Water contamination in the fuel system may cause driveability conditions such as hesitation, stalling, no start, or misfires in one or more cylinders. Water may collect near a single fuel injector at the lowest point in the fuel injection system, and cause a misfire in that cylinder. If the fuel system is contaminated with water, inspect the fuel system components for rust or deterioration.
Ethanol concentrations of greater than 10 percent can cause driveability conditions and fuel system deterioration. Fuel with more than 10 percent ethanol could result in driveability conditions such as hesitation, lack of power, stalling, or no start. Excessive concentrations of ethanol used in vehicles not designed for it may cause fuel system corrosion, deterioration of rubber components, and fuel filter restriction.
Test Procedure
- Test the fuel composition using J 44175 Fuel Composition Tester and J44175-3 Instruction Manual.
- If water appears in the fuel sample, clean the fuel system. Refer to «Fuel System Cleaning»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-introduction__fuel-system-cleaning) .
- Subtract 50 from the reading on the DMM in order to obtain the percentage of alcohol in the fuel sample. Refer to the examples in the Fuel Composition Test Examples table.
- If the fuel sample contains more than 15 percent ethanol, add fresh, regular gasoline to the vehicle's fuel tank.
- Test the fuel composition.
- If testing shows the ethanol percentage is still more than 15 percent, replace the fuel in the vehicle. Refer to «Fuel System Cleaning»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-introduction__fuel-system-cleaning) .
| Frequency (Hz) | Subtract 50 | Ethanol Percent | |
|---|---|---|---|
| Example A | 50 Hz | 50 | 0 |
| Example B | 65 Hz | 50 | 15 |
| Example C | 129 Hz | 50 | 79 |
Fuel Composition Test Examples
Water contamination in the fuel system may cause driveability conditions such as hesitation, stalling, no start, or misfires in one or more cylinders. Water may collect near a single fuel injector at the lowest point in the fuel injection system, and cause a misfire in that cylinder. If the fuel system is contaminated with water, inspect the fuel system components for rust, or deterioration.
Alcohol concentrations of 10 percent or greater in fuel can be detrimental to fuel system components. Alcohol contamination may cause fuel system corrosion, deterioration of rubber components, and subsequent fuel filter restriction. Some types of alcohol are more detrimental to fuel system components than others. Ethanol is commonly used in gasoline, but in concentrations of no more than 10 percent. Some fuels, such as E85, contain a very high percentage of ethanol. Fuel with more than 10 percent ethanol may cause driveability conditions such as hesitation, lack of power, stalling, or no start.
Alcohol in Fuel Testing Procedure
The fuel sample should be drawn from the bottom of the tank so that any water present in the tank will be detected. The sample should be bright and clear. If alcohol contamination is suspected then use the following procedure to test the fuel quality.
- Using a 100 ml (3.4 oz) specified cylinder with 1 ml (0.03 oz) graduation marks, fill the cylinder with fuel to the 90 ml (3.04 oz) mark.
- Add 10 ml (0.34 oz) of water in order to bring the total fluid volume to 100 ml (3.4 oz) and install a stopper.
- Shake the cylinder vigorously for 10-15 seconds.
- Carefully loosen the stopper in order to release the pressure.
- Re-install the stopper and shake the cylinder vigorously again for 10-15 seconds.
- Put the cylinder on a level surface for approximately 5 minutes in order to allow adequate liquid separation.
If alcohol is present in the fuel, the volume of the lower layer, which would now contain both alcohol and water, will be more than 10 ml (0.34 oz). For example, if the volume of the lower layer is increased to 15 ml (0.51 oz), this indicates at least 5 percent alcohol in the fuel. The actual amount of alcohol may be somewhat more because this procedure does not extract all of the alcohol from the fuel.
Particulate Contaminants in Fuel Testing Procedure
The fuel sample should be drawn from the bottom of the tank so that any water present in the tank will be detected. The sample should be bright and clear. If the sample appears cloudy, or contaminated with water, as indicated by a water layer at the bottom of the sample, use the following procedure to diagnose the fuel.
- Using an approved fuel container, draw approximately 0.5 liter (0.13 gal) of fuel.
- Place the cylinder on a level surface for approximately 5 minutes in order to allow settling of the particulate contamination.
Particulate contamination will show up in various shapes and colors. Sand will typically be identified by a white or light brown crystals. Rubber will appear as black and irregular particles. If particles are found clean the entire fuel system thoroughly. Refer to Fuel System Cleaning .
The electronic ignition system uses an individual ignition coil for each cylinder. The powertrain control module (PCM) controls the ignition operation through eight individual ignition control (IC) circuits. Each bank of four ignition coils is connected to the PCM, power, or ground by the following circuits
- Low reference
- Chassis ground
- Ignition 1 voltage
- The appropriate IC circuit
The PCM triggers an ignition coil by grounding the appropriate IC circuit using information from the crankshaft position (CKP) and camshaft position (CMP) sensors.
The number below refers to the step number on the diagnostic table.
- 4: Monitoring the misfire current counters determines if a fault is present.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls | |
| 2 | Crank the engine. Observe the engine speed parameter with a scan tool. Does the scan tool display engine RPM? | Go to Step 3 | Go to Step 13 | |
| 3 | Is DTC P0335, P0336, or P0351-P0358 also set? | Go to Diagnostic Trouble Code (DTC) List | Go to Step 4 | |
| 4 | Idle the engine. Observe the misfire current counters on the scan tool. Does the scan tool display any misfire current counters incrementing? | Go to Step 5 | Go to Intermittent Conditions | |
| 5 | Turn OFF the ignition. Remove the fuel pump relay. Test for spark at each affected cylinder with the J 26792 Spark Tester. Do you have bright blue spark on the cylinders? | Go to Step 6 | Go to Step 7 | |
| 6 | Remove the spark plugs. Inspect the spark plugs for any abnormal conditions or damage. Refer to Spark Plug Inspection . Are the spark plugs in good condition? | System OK | Go to Step 22 | |
| 7 | Measure the spark plug wire resistance. Refer to Spark Plug Wire Inspection . Is the resistance more than the specified value? | 700 ohm/ft | Go to Step 23 | Go to Step 8 |
| 8 | Turn OFF the ignition. Disconnect the affected ignition coil. Turn ON the ignition, with the engine OFF. Probe the ignition voltage circuit of the affected ignition coil with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate? | Go to Step 9 | Go to Step 19 | |
| 9 | Probe the ignition voltage circuit at the affected ignition coil with a test lamp that is connected to the ground circuit of the affected ignition coil. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate? | Go to Step 10 | Go to Step 20 | |
| 10 | Probe the ignition voltage circuit at the affected ignition coil with a test lamp that is connected to the low reference circuit of the affected ignition coil. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate? | Go to Step 11 | Go to Step 15 | |
| 11 | Measure the resistance of the ignition voltage circuit of the affected ignition coil from the fuse that supplies ignition voltage to the affected ignition coil to the harness connector of the affected ignition coil. Is the resistance less than the specified value? | 3 ohm | Go to Step 12 | Go to Step 19 |
| 12 | Measure the resistance of the ground circuit of the affected ignition coil from the harness connector of the affected ignition coil to a good ground. Is the resistance less than the specified value? | 3 ohm | Go to Step 17 | Go to Step 20 |
| 13 | Turn ON the ignition, with the engine OFF. Disconnect the crankshaft position (CKP) sensor. Measure the voltage from the CKP sensor 12-volt reference circuit to a good ground with the DMM. Compare the measured voltage with the system voltage. Is the difference in the voltage more than the specified value? | 0.5 V | Go to Step 14 | Go to Step 16 |
| 14 | Test for a short to ground in the CKP 12-volt reference circuit or the camshaft position (CMP) sensor 12-volt reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 26 | Go to Step 18 | |
| 15 | Test the low reference circuit of the ignition coil for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 26 | Go to Step 18 | |
| 16 | Test for shorted terminals and poor connections at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 26 | Go to Step 21 | |
| 17 | Test for an intermittent and for a poor connections at the ignition coil. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 26 | Go to Step 24 | |
| 18 | Test for shorted terminals and for poor connections at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 26 | Go to Step 25 | |
| 19 | Repair the ignition voltage circuit of the affected ignition coil for one of the following conditions: An open High resistance A short to ground Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 26 | ||
| 20 | Repair the ground circuit of the affected ignition coil for one of the following conditions: An open High resistance Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 26 | ||
| 21 | Replace the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . Did you complete the replacement? | Go to Step 26 | ||
| 22 | Replace the spark plug. Refer to Spark Plug Replacement . Did you complete the replacement? | Go to Step 26 | ||
| 23 | Replace the spark plug wire. Refer to Spark Plug Wire Replacement . Did you complete the replacement? | Go to Step 26 | ||
| 24 | Replace the ignition coil. Refer to Ignition Coil(s) Replacement . Did you complete the replacement? | Go to Step 26 | ||
| 25 | Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement . Did you complete the replacement? | Go to Step 26 | ||
| 26 | Turn OFF the engine for 30 seconds. Start the engine and operate the vehicle. Observe the vehicle performance and driveability. Does the vehicle operate normally? | System OK | Go to Step 3 | |
Electronic Ignition (EI) System Diagnosis
Several states require that a vehicle pass on-board diagnostic (OBD) system tests and the I/M emission inspection in order to renew license plates. This is accomplished by viewing the I/M System Status display on a scan tool. Using a scan tool, the technician can observe the I/M System Status in order to verify that the vehicle meets the criteria that comply with the local area requirements.
Conditions for Updating the I/M System Status
Each system monitor requires at least one, and sometimes several diagnostic tests. The result of each test is reported by a diagnostic trouble code (DTC). A system monitor is complete when either all of the DTCs comprising the monitor have Run and Passed, or when any one of the DTCs comprising the monitor has illuminated the malfunction indicator lamp (MIL). Once the system monitor is complete, the I/M System Status display will indicate YES in the Completed column.
For example, when the HO2S Heater Status indicates YES, either all of the oxygen sensor heater tests have passed or one of the tests has illuminated the MIL. If the vehicle has four heated oxygen sensors, either all four heater circuit tests have passed or one of the heater circuit tests has illuminated the MIL. The I/M System Status will indicate NO under the Completed column when any of the required tests for that system have not run. The following is a list of conditions that would set the I/M System Status indicator to NO
- The vehicle is new from the factory and has not yet been driven through the necessary drive conditions to complete the tests.
- The battery has been disconnected or discharged below operating voltage.
- The control module power or ground has been interrupted.
- The control module has been reprogrammed.
- The control module DTCs have been cleared.
Monitored Emission Control Systems
The OBD II System monitors all emission control systems that are on-board. Not all vehicles have a full complement of emission control systems. For example, a vehicle may not be equipped with secondary air injection (AIR) or exhaust gas recirculation (EGR). The OBD II regulations require monitoring of the following
- The air conditioning system
- The catalytic converter efficiency
- Comprehensive component monitoring-Emission related inputs and outputs
- The evaporative emissions (EVAP) system
- The EGR System
- The fuel delivery system
- Heated catalyst monitoring
- Misfire monitoring
- The oxygen sensor system (O2S or HO2S)
- The oxygen sensor heater system (HO2S heater)
- The AIR system
For the specific DTCs required for each system, refer to Inspection/Maintenance (I/M) System DTC Table . Systems such as fuel delivery, misfire, and comprehensive components may not be listed in a system status list. These tests run continuously and do not require an I/M System Status indicator.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| 1 | Perform Diagnostic System Check - Engine Controls . IMPORTANT: Many DTC related repairs will instruct the technician to clear the DTC information. This procedure will reset ALL of the I/M System Status indicators to NO, and require performing the I/M Complete System Set Procedure. Repair any DTCs or driveability concerns that would prevent the I/M System Status tests from completing. Did you find and repair a DTC or driveability concern? | Go to Step 3 | Go to Step 2 | |
| 2 | Review any service bulletins for software updates that may prevent I/M readiness. Perform any reprogramming or repairs indicated by the service bulletins. Was a reprogramming or repair service required? | Go to Inspection/Maintenance (I/M) Complete System Set Procedure | Go to Step 3 | |
| 3 | Observe the I/M System Status display with a scan tool. Is more than one test indicating a NO status? | Go to Inspection/Maintenance (I/M) Complete System Set Procedure | Go to the I/M System Set Procedure for the indicated systems that have not updated |
| IMPORTANT |
|---|
| Many DTC related repairs will instruct the technician to clear the DTC information. This procedure will reset ALL of the I/M System Status indicators to NO, and require performing the I/M Complete System Set Procedure. |
Inspection/Maintenance (I/M) System Check
The purpose of the inspection maintenance (I/M) Complete System Set Procedure is to satisfy the enable criteria necessary to execute all of the I/M readiness diagnostics, and to complete the trips for those particular diagnostics. When all diagnostic tests are completed, the I/M System Status indicators are set to YES. Perform this test when more than one or all of the I/M System Status indicators are set to NO.
Conditions for Running
Cold Start
- The barometric pressure (BARO) is more than 74 kPa.
- The engine coolant temperature (ECT) is below 30°C (86°F).
- The intake air temperature (IAT) is below 30°C (86°F).
- The difference between the intake air temperature (IAT) and the engine coolant temperature (ECT) is 8°C (14°F) or less.
- The battery voltage is between 9-18 volts.
- The fuel level is between 1/4 and 3/4.
Rough road conditions may prevent some of the tests from running. Extreme high or low ambient temperatures may prevent tests such as for the heated oxygen sensor (HO2S) heater and the evaporative emission (EVAP) system from initiating. If a step is interrupted before completion, perform the remaining portion of the set procedures. Any portion of the set procedure that requires the engine at operating temperature may be repeated. This allows most of the diagnostics to run and the remaining tests can be performed using the individual System Set Procedures.
The scan tool can be used in order to monitor each of the I/M System Status indicators during the I/M Complete System Set Procedure. When all of the indicators for a test step have updated to YES, testing can move on to the next step even if the remaining portion of the test is not complete. For example, step 3 is designed to run the EVAP, AIR, and HO2S tests. The procedure instructs the technician to operate the vehicle in the enable conditions for 6 minutes. If all 3 tests have updated to YES within 4 minutes, you do not need to continue with the enable conditions and testing can advance to the next step.
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step is to run the HO2S heater tests and initiate the EVAP System Test. Preprogramming the scan tool will reduce the amount of time the oxygen sensor heaters operate while verifying the enable criteria.
- 3: This step is to run the EVAP, the AIR and the oxygen sensor tests. The EVAP test begins once the engine coolant reaches a calibrated temperature. The AIR test, if equipped, begins shortly after Closed Loop and the indicated speed is achieved. The oxygen sensor tests begin once the engine is at operating temperature, in Closed Loop Fuel Control, and a calibrated amount of time has elapsed.
- 4: This step is to run the Catalyst Tests. This test runs during the idle period immediately following a cruise period that meets a minimum calibrated RPM and time period.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| CAUTION: Refer to Road Test Caution in Cautions and Notices. | ||||
| 1 | Did you perform the Inspection/Maintenance (I/M) System Check? | Go to Step 2 | Go to Inspection/Maintenance (I/M) System Check | |
| 2 | IMPORTANT: Whenever the ignition is turned ON, ignition positive voltage is supplied to the HO2S heaters. After verifying the enable criteria, turn OFF the ignition for approximately 5 minutes in order to allow the sensors to cool before continuing with the test. Once the engine is started, DO NOT turn the engine OFF for the remaining portion of the set procedure. Preprogram the scan tool with the vehicle information before the ignition is turned ON. Ensure that the vehicle is within the Conditions for Running specified in the supporting text. Turn OFF all of the accessories, including the A/C, and blower fan. Set the vehicle parking brake. Verify the transmission is in Park for automatic transmissions and Neutral for manual transmissions. Start the engine and allow it to idle for the specified time. Is the action complete? | 2 minutes | Go to Step 3 | |
| 3 | In order for the next group of tests to run, the vehicle must operate in the following conditions: Acceleration at part throttle to 90 km/h (55 mph), with this speed maintained until the engine reaches operating temperature. This may be up to 8-10 minutes depending on the start up coolant temperature. Continue operation under these conditions for an additional 6 minutes. Is the action complete? | Go to Step 4 | ||
| 4 | In order for the next group of tests to run, the vehicle must operate in the following conditions: Acceleration at part throttle to 75-89 km/h (45-55 mph) with this speed maintained for 2 minutes. Deceleration to 0 km/h (0 mph). Engine idling for 2 minutes while the following criteria are maintained: Service brake depressed Automatic transmission in drive Manual transmission in neutral with the clutch pedal depressed Is the action complete? | Go to Step 5 | ||
| 5 | Observe the I/M System Status display with a scan tool. Did all of the I/M System Status indicators update to YES? | Go to Step 6 | Go to the I/M System Set Procedure for the systems that have not updated | |
| 6 | Observe the emission related DTC portion of the I/M System Status display with a scan tool. Does the scan tool indicate any emission related DTCs set? | Go to Diagnostic Trouble Code (DTC) List | System OK | |
| CAUTION |
|---|
| Refer to Road Test Caution in Cautions and Notices. |
| IMPORTANT |
|---|
| Whenever the ignition is turned ON, ignition positive voltage is supplied to the HO2S heaters. After verifying the enable criteria, turn OFF the ignition for approximately 5 minutes in order to allow the sensors to cool before continuing with the test. Once the engine is started, DO NOT turn the engine OFF for the remaining portion of the set procedure. |
Inspection/Maintenance (I/M) Complete System Set Procedure
Inspection/Maintenance (I/M) System DTC Table
| System | DTCs Required to Set System Status to YES |
|---|---|
| Catalyst | DTC P0420 or P0430 |
| EVAP | DTC P0455 DTC P0442 DTC P0446 DTC P0496 |
| Oxygen Sensor | DTC P0133 or P0153 DTC P0140 or P0160 DTC P1133 or P1153 DTC P1134 or P1154 |
| Oxygen Sensor Heater | DTC P0135, P0141, P0155, or P0161 |
Inspection/Maintenance (I/M) System DTC Table
The purpose of this test is to satisfy the enable criteria necessary to execute inspection/maintenance (I/M) readiness diagnostics for the catalyst system. The test may be used to set the I/M System Status indicators to YES. The I/M System Status display on the scan tool provides an indication of whether the control module has completed the required tests. The I/M System Status does not indicate that the tests have passed or failed. When all of the diagnostics for a specific system have run and passed, the I/M System Status will update to YES. If a test for a specific system has failed, the I/M System Status will update to YES, indicating a determination was made even if all of the other tests for that system have not run.
- DTCs P0420 and P0430 are not set.
- The barometric pressure is more than 74 kPa.
- The engine coolant temperature (ECT) is between 70-120°C (158-248°F).
- The engine has been running for more than 10 minutes.
- The engine is in Closed Loop fuel control.
- The battery voltage is more than 10-18 volts.
- The intake air temperature (IAT) is between -7° and +85°C (+20° and +185°F).
- The difference between the engine speed and the desired engine speed is less than 200 RPM.
The control module runs a calibrated number of catalyst tests per trip until the Catalyst System Status updates to YES. If the status does not update, the test outlined in this procedure can be repeated until the I/M System Status updates to YES.
If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the service information for an indication of why the test does not complete. Some tests may abort due to changes in the conditions while the test is running. For example, changes in engine load such as a cooling fan or A/C compressor clutch turning ON may cause the test to abort.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you perform the Inspection/Maintenance (I/M) System Check? | Go to Step 2 | Go to Inspection/Maintenance (I/M) System Check |
| 2 | Ensure the vehicle is within the Conditions for Running specified in the supporting text. Turn OFF all of the accessories, e.g., A/C, blower fan, etc. Start the engine and allow it to idle for 5 minutes. CAUTION: Refer to Road Test Caution in Cautions and Notices. IMPORTANT: In order for this test to run, the vehicle must operate in the following conditions: Acceleration at part throttle to 90 km/h (55 mph) with this speed maintained for 5 minutes Deceleration to 0 km/h (0 mph) Engine idling for 2 minutes while the following criteria is maintained: Service brake depressed Automatic transmission in Drive Observe the I/M System Status display with a scan tool. Did the catalyst System Status update to YES? | Go to Step 5 | Go to Step 3 |
| 3 | Observe the DTC Information with a scan tool. Does the scan tool indicate any failed DTCs? | Go to Diagnostic Trouble Code (DTC) List | Go to Step 4 |
| 4 | Refer to the Inspection/Maintenance (I/M) System DTC Table to determine which DTCs are required to run in order to complete this test. Observe the Not Ran Since Code Cleared display with a scan tool. Determine which of the DTCs required for a YES status has not run. Enter the DTC number in the specific DTC menu of the scan tool. Operate the vehicle within the Conditions for Running the DTC, located in the supporting text for the diagnostic table of the DTC. Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat steps 4-6 for any additional required DTCs that have not run. Observe the I/M System Status display with a scan tool. Did the catalyst System Status update to YES? | Go to Step 5 | Go to Diagnostic Aids |
| 5 | Observe the emission related DTC portion of the I/M System Status display with a scan tool. Does the scan tool indicate any emission related DTCs set? | Go to Diagnostic Trouble Code (DTC) List | System OK |
| CAUTION |
|---|
| Refer to Road Test Caution in Cautions and Notices. |
| IMPORTANT |
|---|
| In order for this test to run, the vehicle must operate in the following conditions: Acceleration at part throttle to 90 km/h (55 mph) with this speed maintained for 5 minutes Deceleration to 0 km/h (0 mph) Engine idling for 2 minutes while the following criteria is maintained: Service brake depressed Automatic transmission in Drive |
Inspection/Maintenance (I/M) Catalyst System Set Procedure
The purpose of this test is to satisfy the enable criteria necessary in order to execute the I/M readiness diagnostics for the evaporative emission (EVAP) system. The test may be used in order to set the I/M System Status indicators to YES. The I/M System Status Display on the scan tool provides an indication of when the control module has completed the required tests. The I/M System Status does not indicate that the tests have passed or failed. When all of the diagnostics for a specific system have run and passed and I/M System Status will update to YES. If a test for a specific system has failed, the I/M System Status will update to YES, indicating a determination was made, even if all of the other tests for that system have not run. Performing a visual inspection prior to running the EVAP test may prevent having to repeat the test. A failed or aborted test will require the vehicle to cool down in order to meet the enable criteria to run another test.
- DTCs P0442, P0446, P0455, P0496 are not set.
- The barometric pressure (BARO) is more than 75 kPa.
- The fuel level is between 1/4 and 3/4.
- The battery voltage is between 10-18 volts.
- The engine coolant temperature (ECT) is between 4-30°C (39-86°F).
- The intake air temperature (IAT) is between 4-30°C (39-86°F).
- The difference between the ECT and the IAT is less than 8°C (14°F).
If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the service information for an indication of why the test does not complete. Some tests may abort due to changes in the conditions while the test is running. For example, changes in engine load such as cooling fan or an A/C compressor clutch turning ON may cause the test to abort.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you perform the Inspection/Maintenance (I/M) System Check? | Go to Step 2 | Go to Inspection/Maintenance (I/M) System Check |
| 2 | Ensure the vehicle is within the Conditions for Running specified in the supporting text. Turn OFF all of the accessories, including the A/C and the blower fan. IMPORTANT: Once the engine is started, DO NOT turn the engine OFF for the remainder of the procedure until the test is complete. Start and idle the engine. CAUTION: Refer to Road Test Caution in Cautions and Notices. IMPORTANT: In order for this test to run, the vehicle must operate in the following conditions: Acceleration at part throttle to 72 km/h (45 mph) with this speed maintained until the engine reaches operating temperature. This may be up to 10 minutes, depending on the startup coolant temperature. Continue the operating conditions for an additional 3 minutes after the engine reaches the operating temperature. Decelerate to 0 km/h (0 mph). Idle the engine for 2 minutes. Turn OFF the ignition for 1 hour. After 1 hour, turn ON the ignition. Observe the EVAP System Status with a scan tool. Did the EVAP System Status update to YES? | Go to Step 5 | Go to Step 3 |
| 3 | Observe the DTC Information with a scan tool. Does the scan tool indicate any failed DTCs? | Go to Diagnostic Trouble Code (DTC) List | Go to Step 4 |
| 4 | Refer to Inspection/Maintenance (I/M) System DTC Table to determine which DTCs are required to run in order to complete this test. Observe the Not Ran Since Code Cleared display with a scan tool. Determine which of the DTCs required for a YES status has not run. Enter the DTC number in the Specific DTC menu of the scan tool. Operate the vehicle within the Conditions for Running the DTC, located in the supporting text for the diagnostic table of the DTC. Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat steps 4-6 for any additional required DTCs that have not run. Observe the I/M System Status display with a scan tool. Did the EVAP System Status update to YES? | Go to Step 5 | Go to Diagnostic Aids |
| 5 | Observe the Emission Related DTC portion of the I/M System Status display with a scan tool. Does the scan tool indicate any Emission Related DTCs set? | Go to Diagnostic Trouble Code (DTC) List | System OK |
| IMPORTANT |
|---|
| Once the engine is started, DO NOT turn the engine OFF for the remainder of the procedure until the test is complete. |
| CAUTION |
|---|
| Refer to Road Test Caution in Cautions and Notices. |
| IMPORTANT |
|---|
| In order for this test to run, the vehicle must operate in the following conditions |
Inspection/Maintenance (I/M) Evaporative Emission (EVAP) System Set Procedure
The purpose of this test is to satisfy the enable criteria necessary to execute I/M readiness diagnostics for the oxygen sensor (O2S, HO2S) system. The test may be used to set the I/M System Status to YES. The I/M System Status display on the scan tool provides an indication of whether the control module has completed the required tests. The I/M System Status does not indicate that the tests have passed or failed. When all of the diagnostics for a specific system have run and passed, the I/M System Status will update to YES. If a test for a specific system has failed, the I/M System Status will update to YES, indicating a determination was made, even if all of the other tests for that system have not run.
- DTCs P0131, P0132, P0133, P0134, P0135, P0140, P0151, P0152, P0153, P0154, P0155, P0160, P1133, P1134, P1153, P1154 are not set.
- The fuel level is more than 10 percent.
- The engine coolant temperature (ECT) is more than 50°C (122°F).
- The engine is running in Closed Loop fuel control.
- The engine has been running for more than 7 minutes.
- The battery voltage is between 9-18 volts.
- The mass air flow (MAF) is between 23-50 grams per second.
- The engine speed is between 1,000-2,300 RPM.
- The throttle position (TP) sensor is more than 5 percent.
If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the service information for an indication of why the test does not complete. Some tests may abort due to changes in the conditions while the test is running. For example, changes in engine load such as a cooling fan or A/C compressor clutch turning ON may cause the test to abort.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you perform the Inspection/Maintenance (I/M) System Check? | Go to Step 2 | Go to Inspection/Maintenance (I/M) System Check |
| 2 | Ensure the vehicle is within the Conditions for Running specified in the supporting text. Turn OFF all of the accessories, e.g., A/C, blower fan, etc. Start the engine and allow it to idle for 1 minute. CAUTION: Refer to Road Test Caution in Cautions and Notices. IMPORTANT: In order for this test to run, the vehicle must operate in the following conditions: Acceleration at part throttle to 75-90 km/h (45-55 mph) with this speed maintained for 6 minutes or until the I/M System Status updates to YES. Manual transmissions, either 5 or 6 speed, may require operation in 4th or 5th gear respectively, in order for this test to run. Review the I/M System Status display with a scan tool. Did the HO2S/O2S System Status update to YES? | Go to Step 5 | Go to Step 3 |
| 3 | Observe the DTC Information with a scan tool. Does the scan tool indicate any failed DTCs? | Go to Diagnostic Trouble Code (DTC) List | Go to Step 4 |
| 4 | Refer to the Inspection/Maintenance (I/M) System DTC Table to determine which DTCs are required to run in order to complete this test. Observe the Not Ran Since Code Cleared display with a scan tool. Determine which of the DTCs required for a YES status has not run. Enter the DTC number in the Specific DTC menu of the scan tool. Operate the vehicle within the Conditions for Running the DTC, located in the supporting text for the diagnostic table of the DTC. Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat steps 4-6 for any additional required DTCs that have not run. Observe the I/M System Status display with a scan tool. Did the HO2S/O2S System Status update to YES? | Go to Step 5 | Go to Diagnostic Aids |
| 5 | Observe the Emission Related DTC portion of the I/M System Status display with a scan tool. Does the scan tool indicate any Emission Related DTCs set? | Go to Diagnostic Trouble Code (DTC) List | System OK |
| CAUTION |
|---|
| Refer to Road Test Caution in Cautions and Notices. |
| IMPORTANT |
|---|
| In order for this test to run, the vehicle must operate in the following conditions |
Inspection/Maintenance (I/M) Heated Oxygen Sensor/Oxygen Sensor (HO2S/O2S) System Set Procedure
The purpose of this test is to satisfy the enable criteria necessary to execute inspection/maintenance (I/M) readiness diagnostics for the heated oxygen sensor (HO2S) system. The test may be used to set the I/M System Status to YES. The I/M System Status display on the scan tool provides an indication of whether the control module has completed the required tests. The I/M System Status does not indicate that the tests have passed or failed. When all of the diagnostics for a specific system have run and passed, the I/M System Status will update to YES. If a test for a specific system has failed, the I/M System Status will update to YES, indicating a determination was made, even if all of the other tests for that system have not run.
- The engine coolant temperature (ECT) is less than 50°C (122°F).
- The intake air temperature (IAT) is less than 50°C (122°F).
- The difference between the IAT and the ECT is less than 8°C (14°F).
- The battery voltage is between 11-18 volts.
- The mass air flow (MAF) is less than 23 grams per second.
The HO2S Heater Tests will normally run within the 2 minutes allotted in the procedure. If there is an indeterminate condition, the test may take up to 8 minutes on some vehicles before a decision of pass or fail is made. If the test does not update to YES, it may have failed or aborted due to the loss of enabling conditions. Extremely high ambient temperatures may prevent the HO2S Heater Test from initiating.
If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the service information for an indication of why the test does not complete. Some tests may abort due to changes in the conditions while the test is running. For example, changes in engine load such as a cooling fan or A/C compressor clutch turning ON may cause the test to abort.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Inspection/Maintenance (I/M) System Check? | Go to Step 2 | Go to Inspection/Maintenance (I/M) System Check | |
| 2 | IMPORTANT: Whenever the ignition is turned ON, ignition positive voltage is supplied to the HO2S heaters. After verifying the enable criteria, turn OFF the ignition for approximately 5 minutes to allow the sensors to cool before continuing with the test. Preprogram the scan tool with the vehicle information before the ignition is turned ON. Ensure the vehicle is within the Conditions for Running as specified in the supporting text. Set the vehicle parking brake. Verify the transmission is in Park for automatic transmissions and Neutral for manual transmissions. Turn OFF all of the accessories, e.g., A/C, blower fan, etc. Start the engine and allow it to idle for the specified time or until the I/M System Status indicator updates to YES. Did the HO2S Heater System Status update to YES? | 2 minutes | Go to Step 5 | Go to Step 3 |
| 3 | Observe the DTC information with a scan tool. Does the scan tool indicate any failed DTCs? | Go to Diagnostic Trouble Code (DTC) List | Go to Step 4 | |
| 4 | Refer to the Inspection/Maintenance (I/M) System DTC Table to determine which DTCs are required to run in order to complete this test. Observe the Not Ran Since Code Cleared display with a scan tool. Determine which of the DTCs required for a YES status has not run. Enter the DTC number in the Specific DTC menu of the scan tool. Operate the vehicle within the Conditions for Running the DTC, located in the supporting text for the diagnostic table of the DTC. Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat steps 4-6 for any additional required DTCs that have not run. Observe the I/M System Status display with a scan tool. Did the HO2S Heater System Status update to YES? | Go to Step 5 | Go to Diagnostic Aids | |
| 5 | Observe the Emission Related DTC portion of the I/M System Status display with a scan tool. Does the scan tool indicate any Emission Related DTCs set? | Go to Diagnostic Trouble Code (DTC) List | System OK |
| IMPORTANT |
|---|
| Whenever the ignition is turned ON, ignition positive voltage is supplied to the HO2S heaters. After verifying the enable criteria, turn OFF the ignition for approximately 5 minutes to allow the sensors to cool before continuing with the test. |
Inspection/Maintenance (I/M) Heated Oxygen Sensor (HO2S) Heater System Set Procedure
See also:
• Diagnostic System Check - Engine Controls
• Scan Tool Data List
• Diagnostic System Check - Theft Deterrent
• Charging System Test (With RVC)
• Testing for Intermittent Conditions and Poor Connections
• Connector Repairs
• Power Distribution Schematics
• Service Programming System (SPS)
• Power and Grounding Component Views
• Engine Controls Schematics
• Temperature vs Resistance
• DTC P0106
• Circuit Testing
• Spark Plug Inspection
• Ignition System Specifications
• Spark Plug Wire Inspection
• Oil Consumption Diagnosis
• Engine Compression Test
• Cylinder Head Cleaning and Inspection
• Camshaft and Bearings Cleaning and Inspection
• Piston, Connecting Rod, and Bearings Cleaning and Inspection
• Crankshaft and Bearings Cleaning and Inspection
• Silicon Contamination of Heated Oxygen Sensors Notice
• Heated Oxygen and Oxygen Sensor Notice
• Exhaust Leakage
• DTC P0300
• Restricted Exhaust
• Loss of Coolant (M 35)
• Loss of Coolant (M 82)
• Drive Belt Tensioner Diagnosis
• Cooling Fan Inoperative
• Symptoms - Engine Mechanical
• Wiring Repairs
• Thermostat Diagnosis (LA3, LY9)
• Thermostat Diagnosis (LY7)
• Thermostat Diagnosis (LS6)
• Diagnostic System Check - Engine Electrical
• Exhaust Manifold Cleaning and Inspection
• Throttle Body Cleaning Procedure
• Symptoms - Instrument Panel, Gages and Console
• Diagnostic System Check - Hydraulic Brakes
• Engine Cranks Slowly
• Powertrain Control Module (PCM) Connector End Views
• Engine Controls Connector End Views
• Diagnostic Trouble Code (DTC) List
• Power and Grounding Connector End Views
• Test Probe Notice
• Probing Electrical Connectors
• Troubleshooting with a Digital Multimeter
• Intermittent Conditions
• Engine Controls Schematics
• Diagnostic System Check - Engine Controls
• Testing for Continuity
• Fuel Injector Cleaning Procedure
• Lifting and Jacking the Vehicle
• Fuel System Cleaning
• DTC P1133 or P1153
• Road Test Caution
• Poor Fuel Fill Quality
• Hard Start
• Surges/Chuggles
• Lack of Power, Sluggishness, or Sponginess
• Detonation/Spark Knock
• Hesitation, Sag, Stumble
• Cuts Out, Misses
• Poor Fuel Economy
• Rough, Unstable, or Incorrect Idle and Stalling
• Dieseling, Run-On
• Backfire
• Intermittent Conditions
• Symptoms - Engine Controls
• Inspection/Maintenance (I/M) System DTC Table