Intermittents
Checks
| Action
|
DEFINITION: The problem may or may not turn ON the Malfunction Indicator
Lamp (MIL) or store a Diagnostic Trouble Code (DTC).
|
Preliminary
Checks
|
| • | Refer to
Symptoms
for the
Important Preliminary Checks. |
| • | Do not use the DTC tables for intermittent problems. The fault
must be present in order to locate the problem. If a fault is an intermittent,
the use of the DTC tables may result in the replacement of good parts. |
|
Faulty Electrical Connections or Wiring
| Faulty electrical connections or
wiring can cause most intermittent problems. Perform a careful check of the
suspected circuit for the following items:
| • | Poor mating of the connector halves, or terminals, not fully seated
in the connector body (backed out). |
| • | Improperly formed or damaged terminals. Carefully reform or replace
all the connector terminals in the problem circuit in order to insure the
proper contact tension. |
| • | If poor terminal to wire connection exists, remove the terminal
from the connector body in order to check. Refer to Wiring
Repairs
in Body and Accessories. |
|
Road Test
| Drive the vehicle with a voltmeter connected to a suspected
circuit or use a scan tool if a visual/physical check does not locate the
cause of the problem. Replace the sensor if the wiring and connectors check
OK and a DTC other than DTC 44 AND 45 was stored for a circuit having a sensor.
|
Intermittent Malfunction Indicator Lamp (MIL)
| The following can cause an intermittent
MIL and no DTCs:
| • | An electrical system interference caused by a defective relay
and an ECM driven solenoid, or switch can cause a sharp electrical surge.
Normally, the problem will occur when the faulty component is operating. |
| • | The improper installation of electrical devices, such as lights,
2-way radios, electric motors, etc. |
| • | Route the Ignition Control (IC) wires away from the spark plug
wires, the ignition system components, and the generator. The wire for the
engine ground from the ECM to the ignition system should be a good ground. |
| • | The ignition secondary shorted to ground. |
| • | The Malfunction Indicator Lamp (MIL) circuit or the diagnostic
test terminal intermittently shorted to ground. |
| • | The ECM grounds. Refer to Component Locations
. |
|
Loss of DTC Memory
| In order to check for the loss of the DTC Memory, disconnect
the Throttle Position (TP) sensor, and idle the engine until the Malfunction
Indicator Lamp comes ON. DTC 22 should store and remain in the memory when
turning OFF the ignition for at least 10 seconds. If the DTC does
not remain in the memory for 10 seconds, the ECM is faulty.
|
