TROUBLESHOOTING GUIDE — 23 SURGES WHILE CRUISING
F-54prose procedure23 SURGES WHILE CRUISING
DESCRIPTION: Unexpected change in engine speed which is usually repetitive
NOTE
[TROUBLESHOOTING HINTS]
① Air/Fuel mixture too lean or too rich
• Fuel injection control malfunction
• Air leakage of intake air system
• Fuel line pressure low
• Evaporative emission control malfunction
• Spark advance control malfunction
Troubleshooting Guide (steps 1–5)
1
INSPECTIONCheck if "00" is displayed on Self-Diagnosis Checker with ignition switch ON (page F-78)
RESULTYes
ACTIONGo to next step
1
INSPECTIONCheck if "00" is displayed on Self-Diagnosis Checker with ignition switch ON (page F-78)
RESULTNo
ACTIONMalfunction Code No. displayed
Check for cause (Refer to specified check sequence) (page F-80)
"88" flashes
Check ECU terminal 1F voltage (page F-128)
Voltage: Approx. 12V (Ignition switch ON)
- If OK, replace ECU (page F-127)
- If not OK, check wiring between ECU and Self-Diagnosis Checker (page F-7)
2
INSPECTIONCheck switches for correct operation with Self-Diagnosis Checker Monitor Lamp and ignition switch ON (page F-89)
RESULTYes
ACTIONGo to next step
2
INSPECTIONCheck switches for correct operation with Self-Diagnosis Checker Monitor Lamp and ignition switch ON (page F-89)
RESULTNo
ACTIONLamp not ON/OFF with specified switch
Check for cause (Refer to specified check sequence) (page F-90)
Lamp always ON
Check wiring between ECU terminal 1D and Self-Diagnosis Checker (page F-7)
3
INSPECTIONDisconnect oxygen sensor connector and check if condition improves
RESULTYes
ACTIONCheck oxygen sensor (page F-138)
3
INSPECTIONDisconnect oxygen sensor connector and check if condition improves
RESULTNo
ACTIONGo to next step
4
INSPECTIONCheck if ECU terminal voltages are OK (page F-128)
RESULTYes
ACTIONGo to next step
4
INSPECTIONCheck if ECU terminal voltages are OK (page F-128)
RESULTNo
ACTIONCheck for cause (Refer to "Check Point for Each Terminal") (page F-131)
5
INSPECTIONCheck if throttle linkage is correctly installed and operates freely
RESULTYes
ACTIONGo to next step
5
INSPECTIONCheck if throttle linkage is correctly installed and operates freely
RESULTNo
ACTIONCorrect, clean, or replace as required any binding or damaged linkage, and adjust cable deflection at throttle body (page F-96)
See also
F-78SELF-DIAGNOSIS FUNCTIONF-80SELF-DIAGNOSIS FUNCTIONF-128CONTROL SYSTEM - Engine Control Unit Terminal Voltage TableF-127CONTROL SYSTEM - Engine Control Unit InspectionF-7OUTLINE - WIRING DIAGRAMF-89SELF-DIAGNOSIS FUNCTIONF-90SELF-DIAGNOSIS FUNCTIONF-138CONTROL SYSTEMF-131CONTROL SYSTEM - Check Point for Each TerminalF-96INTAKE AIR SYSTEM