CHART - 1 - INTERMITTENT CODE OR A SYMPTOM AND NO CODES (Cont'd)

TM 9-2320-364-20-1

Section IV. TROUBLESHOOTING CHARTS (Cont.)

D. CHART - 1 - INTERMITTENT CODE OR A SYMPTOM AND NO CODES (Cont'd)

STEP/SEQUENCE

C 1-2

Diagnosis of an Intermittent

Code or Symptom

NOTE: Do not use any other procedures in this manual (except for the suggestions listed below) when trying

to solve an intermittent problem. Use of any other procedures for this kind of problem can result in the replace-

ment of non-defective parts.

Many intermittent problems are caused by faulty electrical connectors or wiring. Diagnosis must include a

careful inspection of the indicated circuit wiring and connectors. Example: an intermittent Code 35 (Oil Pres-

sure Sensor High) should cause suspicion of a problem in the following areas associated with the Oil Pressure

Sensor.

1. Wire #'s 530 (signal line), 416 (+5 volt line) or 452 (ground line).

2. The Oil Pressure Sensor connector or ECM connector.

3. An intermittent in the Oil Pressure Sensor (least likely).

A good check list to run through includes the following:

1. Check for poor mating of the connector halves or terminals not fully seated in the connector body

("backed-out" terminals).

2. Look for improperly formed or damaged terminals. All connector terminals in the problem circuit should

be carefully reformed to contact tension.

3. Electrical system interference caused by a defective relay, ECM driven solenoid, or a switch causing

an electrical surge. Look for problems with the charging system (alternator, etc.). In certain cases, the

problem can be made to occur when the faulty component is operated (as in the case of a relay).

After repairs or adjustments have been made, clear the codes and confirm that the "Check Engine" light does

not come on (except for the 5 second bulb check when the ignition is first turned on). Also run the engine to

see if that problem is cured. If the "Check Engine" light stays on, refer to the START-1 Chart on page 2-539.

Refer to the DDR instructions manual. Using the "Snapshot" function may assist in isolating the cause for the

problem. This function is useful in troubleshooting many areas of the DDEC System.

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