How to Proceed With Troubleshooting

HOW TO PROCEED WITH TROUBLESHOOTING





Perform troubleshooting in accordance with the procedures.

[1] CUSTOMER PROBLEM ANALYSIS
Using the customer problem analysis check sheet for reference, ask the customer in as much detail as possible about the problem.

[2] CHECK AND CLEAR THE DIAGNOSTIC CODES (PRECHECK)
In case that the Anti-Lock warning light lights up, and the A.B.S. does not operate, the ECU stores diagnostic codes corresponding to the problem in memory.

Before confirming the trouble, first check the diagnostic codes to see if there are any trouble codes stored in memory. When there are trouble codes, make a note of them, then clear them and proceed to"[3] Problem Symptom Confirmation".

[3] PROBLEM SYMPTOM CONFIRMATION, [4] SYMPTOM SIMULATION
Confirm the problem symptoms. If the problem does not reoccur, be sure to simulate the problem by mainly checking the circuits indicated by the diagnostic code in step [2], using "Problem simulation method".

[5] DIAGNOSTIC CODE CHECK
Check the diagnostic codes. Determine if the abnormality in the sensors or the wire harness.

If a diagnostic code is output, proceed to " [6] Diagnostic Code Chart". If the normal code is output, proceed to " [7] Problem Symptoms Chart".

Be sure to proceed to" [6] Diagnostic Code Chart" after the steps [2] and [3] are completed.

If troubleshooting is attempted only by following the malfunction code stored in the memory, errors could be made in the diagnosis.

[6] DIAGNOSTIC CODE CHART
If a trouble code is confirmed in the diagnostic code check, proceed to the inspection procedure indicated by the matrix chart for each diagnostic code.

[7] PROBLEM SYMPTOMS CHART
If the normal code is confirmed in the diagnostic code check, perform inspection in accordance with the inspection order in the problem symptoms chart.

[8] CIRCUIT INSPECTION
Proceed with diagnosis of each circuit in accordance with the inspection order confirmed in [6] and [7]. Determine whether the cause of the problem is in the sensor, actuators, wire harness and connectors, or the ECU.

[9] SENSOR CHECK
Use the ANTILOCK warning light to check if each of the signals from the brakes, parking brakes, shift position and speed sensors are being input correctly to the ECU. Instructions for this check are given in the circuit Inspection.

[10] REPAIRS
After the cause of the problem is located, perform repairs by following the inspection and replacement procedures in this manual.

[11] CONFIRMATION TEST
After completing repairs, confirm not only that the malfunction is eliminated, but also conduct a test drive, etc., to make sure the entire A.B.S. system is operating correctly. (In vehicles with the TRAC system, also check the TRAC system.)