Component Tests and General Diagnostics
DIAGNOSISTo ensure that the trouble diagnosis is done accurately and smoothly, observe "PRECAUTIONS in DIAGNOSING TROUBLES" and follow "ABS DIAGNOSTIC FLOW TABLE".
PRECAUTIONS IN DIAGNOSING TROUBLES
^ If the vehicles was operated in any of the following ways, ABS warning lamp may light momentarily but this does not indicate anything abnormal in ABS.
- The vehicle was driven with parking brake pulled.
- The vehicle was driven with brake dragging.
- The vehicle was stuck in mud, sand, etc.
- Wheel spin occurred while driving.
- Wheel(s) was rotated while the vehicle was jacked up.
^ Be sure to use the trouble diagnosis procedure as described in the flow table. Failure to follow the flow table may result in incorrect diagnosis. (Some other diagnosis trouble code may be stored by mistake in the memory of ABS control module during inspection.)
^ When disconnecting ABS hydraulic unit control module connector (1), pull up lock (2) of connector.
When connecting, set the connector on ABS hydraulic unit control module assembly and push the lock (2) down.
ABS DIAGNOSTIC FLOW TABLE
Refer to the following pages for the details of each step.
1. MALFUNCTION ANALYSIS
a) Customer Complaint Analysis
Record details of the problem (failure, complaint) and how it occurred as described by the customer.
For this purpose, use of such a questionnaire form as shown below will facilitate collecting information to the point required for proper analysis and diagnosis.
CUSTOMER QUESTIONNAIRE (EXAMPLE)
b) Problem Symptom Confirmation Check if what the customer claimed in "CUSTOMER QUESTIONNAIRE" is actually found in the vehicle and if that symptom is found, whether it is identified as a failure. (This step should be shared with the customer if possible.) Check warning lamps related to brake system referring to "EBD WARNING LAMP (BRAKE WARNING LAMP) CHECK" and "ABS WARNING LAMP CHECK".
c) Diagnostic Trouble Code (DTC) Check, Record and Clearance
Perform "DIAGNOSTIC TROUBLE CODE CHECK" procedure, record it and then clear it.
If the malfunction DTC which was once displayed and then cleared cannot be detected (indicated) again when the ignition switch is turned ON, attempt to diagnose the trouble based on the DTC recorded in this step may mislead the diagnosis or make diagnosing difficult. Proceed to Step 2) to check control module for proper self-diagnosis function.
If the malfunction DTC, which was once displayed and then cleared can be detected (indicated) again when ignition switch is turned ON, proceed to Step 3).
2. DRIVING TEST
Test drive the vehicle at 40 km/inch for more than a minute and check if any trouble symptom (such as abnormal lighting of ABS warning light) exists.
If the malfunction DTC is confirmed again at ignition switch ON, driving test as described in above is not necessary. Proceed to Step 3).
3. DIAGNOSTIC TROUBLE CODE CHECK
Recheck diagnostic trouble code referring to "DTC CHECK".
Displaying & Reading Trouble Codes
4. DIAGNOSTIC TROUBLE CODE FLOW TABLE
According to Diagnostic flow table for the diagnostic trouble code confirmation in Step 3), locate the cause of the trouble, namely in a sensor, switch, wire harness, connector, actuator assembly or other part and repair or replace faulty parts.
5. "DIAGNOSIS" IN "BRAKES"
Check the parts or system suspected as a possible cause referring to "DIAGNOSIS" in "BRAKES" and based on symptoms appearing on the vehicle (symptom obtained through Steps 1)-a, 1)-b and 2) and repair or replace faulty parts, if any).
6. CHECK FOR INTERMITTENT PROBLEM
Check parts where an intermittent trouble is easy to occur (e.g., wire harness, connector, etc.), referring to "INTERMITTENT TROUBLE" in "GENERAL INFORMATION" and related circuit of trouble code recorded in Step 1)-c.
7. FINAL CONFIRMATION TEST
Confirm that the problem symptom has gone and the ABS is free from any abnormal conditions. If what has been repaired is related to the malfunction DTC, clear the DTC once and perform test driving and confirm that no DTC is indicated.