Supplemental restraint system--Remove malfunctionDiagnostic procedure
When starting to check, firstly, use special diagnostic tool and ECU to make diagnostic communication to
find the reason of malfunction, if communication could not implement, make following inspection:
(1) Check the battery
a. Measure the voltage of battery
b. Is the voltage higher than 9V?
Yes: make next operation,
No: Power supply of battery is lack, check the charging/discharging system, then make step 5.
(2) Check the conduction of wiring harness between ECU and combination meter.
a. Set ignition switch at LOCK position,
b. Cut off cathode of battery,
c. Open the defending board of central channel,
d. Disconnect the connector of instrument package ,
e. Connect the cathode of battery,
f. Set ignition switch at ON position,
g. Check whether the terminal voltage of corresponding connector of instrument is 12V (connecting
wire of power supply and instrument)
Yes: make next step,
No: check the circuit part, then make step 5 after repairing it.
h. Set ignition switch at LOCK position,
i. Check whether the corresponding terminal of instrument connector conducts with corresponding
terminal of diagnostic interface (diagnose two ends of K wire),
Yes: make next step,
No: repair or change the wiring harness, then make step 5.
j. Guarantee cathode of battery is cut off and keep this state for one minutes at least, cut off connec-
tor of ECU.
k. Disconnect the plug of instrument package,
l. Check whether it conducts between ECU plug voltage, K wire, airbag indicating light terminal and
plug of instrument package?
Yes: make next operation,
No: change the wiring harness, then make the step 5.
m. Disassemble the ECU to check whether the terminal is good, and the short circuit stick is broken.
Yes: change the ECU,
No: connect the ECU connector again, then make next operation.
zPower supply of battery is lack
zECU has inner malfunction
zIndicating light of combination meter safety airbag has
malfunction
zPlug connection of ECU has malfunction
zPlug of combination meter contacts badly
zPower supply fuse of ECU is cut off or contacts badly
zPlug terminal of ECU contacts badly
zWiring harness between plug terminal and grounding of
ECU contacts badly
zSafety airbag circuit at the side of driver or passenger
has malfunction.Malfunction Test state Possible reasonIndicating light of
safety airbag sys-
tem illuminates
usuallyIndicating light of safety
airbag system illumi-
nates usually- Indicating light of safety airbag system illuminates usually
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