Identifying Intermittent Conditions
Many intermittent conditions occur with harness or connector movement due to engine torque, rough pavement, vibration or physical movement of a component. Refer to the following for a list to help determine an intermittent condition
- Moisture, and water intrusion in connectors, terminals, and components
- Connector mating
- Terminal contact
- High circuit or component resistance - High resistance can include any resistance, regardless of the amount, which can interrupt the operation of the component.
- Harness that is located too tight, or chaffed circuits
- High or low ambient temperature
- High or low engine coolant temperatures
- High underhood temperatures
- Heat build up in component or circuit due to circuit resistance, poor terminal contact, or high electrical load
- High or low system voltage
- High vehicle load conditions
- Rough road surface
- Electro-magnetic Interference (EMI)/circuit interference from relays, solenoids or other electrical surge
- Incorrect installation of non-factory, aftermarket, and after factory add on accessories
If an intermittent is determined, refer to Testing for Intermittent Conditions and Poor Connections for specific strategies in diagnosing intermittent conditions.
Visual/Physical Check
Note. Use the connector test adapter kit J 35616-A for any test that requires probing the following items: The PCM harness connectors The electrical center fuse/relay cavities The component terminals The component harness connector Using this kit will prevent damage caused by the improper probing of connector terminals.
Several of the symptom procedures call for a careful visual and physical inspection. This can lead to correcting a condition without further tests and can save time. This inspection should include the following areas
- Ensure that the control module grounds are clean, tight, and correctly located. Refer to «Master Electrical Component List»(ref-242988-S13173405132006082100000) and «Power and Grounding Connector End Views»(ref-243019-S37567670392006082100000) .
- Inspect vacuum hoses for splits, kinks, and proper connections, as shown on the Vehicle Emission Control Information label. Inspect thoroughly for any type of a leak or a restriction. Refer to «Emission Hose Routing Diagram»(ref-242989-S25798440602006082100000) and «Evaporative Emissions (EVAP) Hose Routing Diagram»(ref-243018-S24601802442006082100000) .
- Inspect for a dirty or restricted air filter.
- Inspect for water intrusion in the mass air flow/intake air temperature (MAF/IAT) sensor connector, heated oxygen sensor (HO2S) connectors, control module connectors or any other harness connectors.
- Inspect the air intake ducts, particularly between the MAF sensor and the throttle body for the following conditions: Collapsed Damaged areas Looseness Incorrect installation Leaking
- Inspect for air leaks at the throttle body mounting area, the mass air flow (MAF) sensor and intake manifold sealing surfaces.
- Inspect the wiring harness for the following conditions: Poor connections Pinches Cuts
- Inspect for loose, damaged, unseated, or missing sensors/components.
- Inspect terminals for corrosion and correct contact.
Poor Fuel Fill Quality
| Problem | Causes |
|---|---|
| DEFINITION: During the fueling process a continual, occasional or no fuel nozzle shut-off condition has occurred. | |
| Difficult to fill | Fuel fill limiter vent valve stuck closed Evaporative emission (EVAP) canister restricted EVAP vent valve stuck closed Restricted vapor lines High fuel temperature Fuel filler hose is pinched or kinked Ignition switch ON (vent valve closed) |
| Over fill | Pressure relief valve is stuck open or leaking Fill limiter vent valve stuck open or leaking |
| Pre-mature shut-off of the fuel dispensing nozzle occurs immediately after engaging dispensing nozzle, tank empty | Faulty dispensing nozzle Restricted vapor lines or fuel fill pipe High fuel temperature Inlet check valve at tank stuck closed, fill pipe full of fuel Fuel tank full, gage not accurate |
| Pre-mature shut-off of the fuel dispensing nozzle, more than 1/8 of tank capacity dispensed | Kinked, pinched or plugged lines in fuel tank vent system EVAP vent valve stuck closed or restricted EVAP canister restricted Fuel limiting vent valve stuck closed or obstruction at top of fuel tank Fill pipe design concern exists, check with technical assistance |
| Fuel Spitback | Restricted EVAP canister High fuel temperature Ignition switch ON, EVAP vent valve closed |
Poor Fuel Fill Quality
Reference Information
Schematic Reference
Engine Controls Schematics
Scan Tool Reference
- «Scan Tool Data List»(ref-243059-S35183172092006082100000)
- «Scan Tool Data Definitions»(ref-243059-S28585364262006082100000)
Connector End View Reference
- «Powertrain Control Module (PCM) Connector End Views»(ref-242989-S23987502632006082100000)
- «Engine Controls Connector End Views»(ref-242989-S06774515832006082100000)
Electrical Information Reference
- «Circuit Testing»(ref-242973-S03159704652006082100000)
- «Connector Repairs»(ref-242973-S32323876832006082100000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-242973-S38322986792006082100000)
- «Wiring Repairs»(ref-242973-S18890039002006082100000)
Circuit/System Verification
The MIL should turn ON and OFF when commanded with a scan tool.
Repair Procedures
| IMPORTANT | Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. |
- Control Module References for ECM replacement, setup and programming
- «Instrument Panel Cluster (IPC) Replacement»(ref-242974-S41622145992006082100000)
Schematic Reference
Engine Controls Schematics
Connector End View Reference
- «Powertrain Control Module (PCM) Connector End Views»(ref-242989-S23987502632006082100000)
- «Engine Controls Connector End Views»(ref-242989-S06774515832006082100000)
Electrical Information Reference
- «Circuit Testing»(ref-242973-S03159704652006082100000)
- «Connector Repairs»(ref-242973-S32323876832006082100000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-242973-S38322986792006082100000)
- «Wiring Repairs»(ref-242973-S18890039002006082100000)
Scan Tool Reference
- «Scan Tool Data List»(ref-243059-S35183172092006082100000)
- «Scan Tool Data Definitions»(ref-243059-S28585364262006082100000)
Attempt to start the engine. Engine should start and run.
| IMPORTANT | Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. |
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Engine Controls Connector End Views
Electrical Information Reference
- «Circuit Testing»(ref-242973-S03159704652006082100000)
- «Connector Repairs»(ref-242973-S32323876832006082100000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-242973-S38322986792006082100000)
- «Wiring Repairs»(ref-242973-S18890039002006082100000)
Special Tools Required
CH-47976 Active Fuel Injector Tester
Schematic Reference
Engine Controls Schematics
Connector End View Reference
- «Powertrain Control Module (PCM) Connector End Views»(ref-242989-S23987502632006082100000)
- «Engine Controls Connector End Views»(ref-242989-S06774515832006082100000)
Electrical Information Reference
- «Circuit Testing»(ref-242973-S03159704652006082100000)
- «Connector Repairs»(ref-242973-S32323876832006082100000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-242973-S38322986792006082100000)
- «Wiring Repairs»(ref-242973-S18890039002006082100000)
Scan Tool Reference
- «Scan Tool Data List»(ref-243059-S35183172092006082100000)
- «Scan Tool Data Definitions»(ref-243059-S28585364262006082100000)
Special Tools Required
- CH-48027 Digital Pressure Gage
- J 39021-410 Fuel Injector Harness Adapter
- J 39021 Fuel Injector Coil and Balance Tester
- J 39021-210 Injector Tester Adapter Box
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
FUEL INJECTOR REPLACEMENT
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 emission (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)
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 | Yes | No |
|---|---|---|---|
| 1 | Perform the Diagnostic System Check - Vehicle in Vehicle DTC Information. 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 Inspection/Maintenance (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 system that has 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 Inspection/Maintenance (I/M) Complete System Set Procedure. |
Inspection/Maintenance (I/M) System Check