Symptom Related Diagnostic Procedures
ENGINE CONTROL SYSTEM DIAGNOSISINTRODUCTION TO ENGINE CONTROL SYSTEM DIAGNOSIS
If there is a malfunction in the engine control system, the accelerator cable, accelerator pedal or throttle lever may be faulty.
Symptom Chart:
SYMPTOM CHART
SYMPTOM PROCEDURES
INSPECTION PROCEDURE 1: Throttle Valve will not Fully Open or Close
DIAGNOSIS
STEP 1. Check the accelerator cable adjustment.
Q: Is the accelerator cable properly adjusted?
YES: Go to Step 2.
NO: Adjust the accelerator cable, and then go to Step 3.
STEP 2. Check the accelerator pedal position sensor assembly.
Check that the lever of the accelerator pedal position sensor assembly moves smoothly by moving it by hand.
Q: Does the lever of the accelerator pedal position sensor assembly move smoothly?
YES: Go to Step 3.
NO: Replace the accelerator pedal position sensor assembly, then go to Step 3.
STEP 3. Retest the system.
Q: Does the throttle valve fully open and close?
YES: The procedure is complete.
NO: Return to Step 1.
INSPECTION PROCEDURE 2: Accelerator Pedal Operation is not Smooth (Over Acceleration)
DIAGNOSIS
STEP 1. Check the accelerator pedal.
Q: Is the accelerator pedal loose?
YES: Tighten the fasteners, then go to Step 4.
NO: Go to Step 2.
STEP 2. Check the accelerator cable wiring.
Q: Is the accelerator cable routing bent sharply?
YES: Correct the cable routing, then go to Step 4.
NO: Go to Step 3.
STEP 3. Check the accelerator cable lubricant.
Q: Is the accelerator cable lubricated sufficiently?
YES: There is no action to be taken.
NO: Refill or replace the lubricant, then go to Step 4.
STEP 4. Retest the system.
Q: Does the accelerator pedal work normally?
YES: The procedure is complete.
NO: Return to Step 1.