MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-565
INSPECTION PROCEDURE 9: Idle speed is high (improper idle speed).
.
COMMENT
•
In such cases as the above, the cause is proba-
bly that the intake air volume during idle is too
great.
.
TROUBLESHOOTING HINTS (The most likely
causes for this case:)
•
Malfunction of the IAC system.
•
Malfunction of the throttle body.
DIAGNOSIS
Required Special Tool:
•
MB991502: Scan Tool (MUT-II)
STEP 1. Using scan tool MB991502, read the diagnostic
trouble code (DTC).
CAUTION
To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC is output?
YES :
Refer to, Diagnostic Trouble Code Chart
.
NO :
Go to Step 2.
STEP 2. Check the idle air control (IAC) motor operation
sound.
(1) Check that the engine coolant temperature is 20
°
C (68
°
F)
or below.
NOTE: Disconnecting the engine coolant temperature sen-
sor connector and connecting the harness side of the con-
nector to another engine coolant temperature sensor that is
at 20
°
C (68
°
F) or below is also okay.
(2) Check the operation sound of the IAC motor can be heard
after the ignition is switched to the "ON" position (but
without starting the engine).
•
An operation sound should be heard.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Did you hear the operation sound?
YES :
Go to Step 3.
NO :
Refer to, DTC P0506
−
Idle Control System RPM
Lower Than Expected
, DTC P0507
−
Idle
Control System RPM Higher Than Expected
.
AKX01177
16 PIN
MB991502
AB
ACX02523AI
IDLE AIR
CONTROL
MOTOR
CONNECTOR:B-34