Checks
| Action
|
DEFINITION: The problem
may or may not turn ON the MIL or store a DTC. There is a customer concern,
but the symptom cannot currently be duplicated, or the DTC diagnostic table
indicates the fault not present at this time.
|
Preliminary Checks
|
| • | Refer to Important Preliminary Checks in
Symptoms |
| • | The fault must be present in order to be correctly diagnosed.
If the fault is intermittent, the use of DTC tables may result in the unnecessary
replacement of good parts. |
|
Electrical Connections or Wiring
| Usually, intermittent conditions are caused
by electrical connections or by wiring.
Determine which circuit is suspected of having an intermittent condition.
Any DTCs set with a fault not present can indicate the intermittent.
Check the suspected circuit for the following conditions:
| • | Incorrectly-mated connectors |
| • | Incorrectly seated connectors |
| • | Incorrectly formed terminals or damaged terminals |
| | Use the terminal repair kit in order to check J-38125
for the correct terminal tension. |
| • | Poor terminal-to-wire connections |
| • | Broken wires inside the insulation. |
| • | Damaged insulation that allows moisture to enter the wiring.The
conductor can corrode inside the insulation with little visible evidence.
Look for swollen sections or for stiff sections of the wire in the suspected
circuit. |
Refer to
Wiring Repairs
and
Connector Repairs
to in Wiring Systems.
|
Road Test
| Perform the following tests with two people, in order to
ensure the safe operation of the vehicle.
| • | Drive the vehicle while monitoring the suspected circuit with
a scan tool J 39200
or with
a digital multimeter. If the malfunction occurs, look for an abnormal scan
tool reading or for an abnormal voltage. An abnormal reading or an abnormal
voltage indicates that there may be a malfunction in the circuit. |
| • | If the intermittent causes a DTC to set, monitor the diagnostic
on the scan tool. The test has not run if the DTC appears in the Not Ran
Since Code Cleared. If the DTC does not appear under Not Ran Since Code Cleared,
the DTC diagnostic has run. If the MIL is not illuminated and there is not
a pending DTC Status in DTC Information, the DTC diagnostic has passed. Clear
the DTCs in order to view the current status of the Not Ran Since Code Cleared
list. The Not Ran Since Code Cleared list only indicates the test has run,
not if the test has passed or failed. Check the DTC Information for CURRENT
status or for PENDING status, in order to determine the result of the test. |
|
Scan Tool
| Use the following scan tool features in order to locate
an intermittent condition:
| | The scan tool snapshot feature can be triggered to capture the engine
parameters if a malfunction occurs. This stored information can be reviewed
and compared to the Typical Scan Tool Data Values or the data values of a
similarly equipped vehicle. |
| • | The Freeze Frame and Failure Records |
| | The Freeze Frame and Failure Records are stored if certain DTCs set.
The Freeze Frame Failure Records can aid in reproducing the driving conditions
that were present when a DTC set. The engine parameters are also stored. This
information can be compared to the typical data values or
Engine Scan Tool Data List
to the values from a similarly equipped
vehicle. |
| | The Freeze Frame and Failure Records will be erased when the DTC Information
is cleared. |
|
Intermittent Malfunction Indicator Lamp (MIL)
| The following conditions may cause
intermittent MIL operation without any DTCs set:
| • | A faulty relay, a control-module-driven solenoid, or a switch
that causes an electrical system interference. Usually, the symptom will occur
when the faulty component is operating. |
| • | An ignition control (IC) wire that is routed near to the generator
or near the secondary ignition system components. |
| • | An ignition system secondary voltage that is arcing and is shorted
to ground. |
| • | A faulty ignition control circuit or a faulty ignition module
ground. |
| • | An MIL control circuit that is shorting to ground. |
| • | Any faulty diodes in the generator or in the charging system circuits. |
| • | The incorrect installation of add-on electrical devices. Check
any of the following add-on devices: |
|
Loss of DTC Memory
| In order to check for the correct DTC Memory function,
perform the following procedure:
- Observe the Conditions for Running the DTC for the TP Sensor Circuit
Low Voltage DTC.
- Disconnect the TP sensor connector.
- Operate the vehicle within the Conditions For Running The DTC.
- The MIL should illuminate upon completion of the Conditions For
Running The DTC. Two key cycles or drive trips may be required.
- A TP Sensor Circuit Low Voltage DTC should remain in memory after
the ignition is OFF.
Failure to store a DTC or a DTC that does not remain in memory may indicate
a faulty PCM.
|
Additional Checks
|
| • | Check for open diodes that may cause electrical interference. |
| • | The incorrect installation of add-on electrical devices. Check
the following devices: |
| • | If the intermittent fault involves a particular component, observe
the component display on a scan tool while moving the related connectors and
the related wiring. A change in the scan tool display can indicate the location
of the fault. |
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