Mitsubishi Grandis. Manual - part 742
TROUBLESHOOTING
MULTIPORT FUEL INJECTION (MPI)
13A-219
• When the throttle valve control servo relay turns
ON, battery voltage is supplied by the throttle
valve control servo relay (terminal No. 1) to the
engine-ECU <M/T> or engine-A/T-ECU <A/T>
(terminal No. 132).
FUNCTION
• When the ignition switch ON signal is input into
the engine-ECU <M/T> or engine-A/T-ECU
<A/T>, the engine-ECU <M/T> or
engine-A/T-ECU <A/T> turns ON the Throttle
valve control servo.
TROUBLE JUDGMENT
Check Condition
• Ignition switch is in ON position.
Judgement Criterion
• The power line voltage of the electronic controlled
throttle system is 4.0 V or less for 1 second.
PROBALE CAUSE
• Failed throttle valve return spring
• Open/short circuit in throttle valve control servo
circuit or loose connector contact.
• Failed engine-ECU <M/T>
• Failed engine-A/T-ECU <A/T>
DIAGNOSIS
STEP 1. Connector check: B-12X throttle valve
control servo relay connector
Q: Is the check result normal?
YES :
Go to Step 2 .
NO :
Repair or replace.
STEP 2. Check throttle valve control servo relay
itself.
• Check throttle valve control servo relay itself
(Refer to
Q: Is the check result normal?
YES :
Go to Step 3 .
NO :
Repair.
STEP 3. Perform voltage measurement at B-12X
throttle valve control servo relay connector.
• Remove relay, and measure at relay box side.
• Voltage between terminal No. 4 and earth.
OK: System voltage
Q: Is the check result normal?
YES :
Go to Step 4 .
NO :
Check and repair harness between B-12X
(terminal No. 4) throttle valve control servo
relay connector and battery.
• Check power supply line for
open/short circuit.
AK300992
2
1
3
4
AC
B-12X
Connector: B-12X
Relay box’s
triangle marks
Harness side
connector
AK300992
2
1
3
4
AC
B-12X
Connector: B-12X
Relay box’s
triangle marks
Harness side
connector