MPI – Troubleshooting
13-39
INSPECTION PROCEDURE 28
Power steering fluid pressure switch system
Probable cause
The presence or absence of power steering load is input to the engine-ECU.
The engine-ECU controls the idle speed control (ISC) servo based on this input.
D Malfunction of power steering fluid pressure switch
D Improper connector contact, open or short-circuited
harness wire
D Malfunction of the engine-ECU
Check the power steering fluid pressure switch.
NG
Replace
OK
Measure at the power steering fluid pressure switch connector
A-101.
D Disconnect the connector, and measure at the harness side.
D Voltage between 1 and earth (Ignition switch: ON)
OK: System voltage
NG
Check the following
connectors: A-28, B-60
NG
Repair
OK
Check trouble symptom.
NG
Check harness wire be-
tween engine-ECU and
power steering fluid pres-
sure switch connector.
NG
Repair
OK
Replace the engine-ECU.
OK
Check the following
connector: A-101
NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
INSPECTION PROCEDURE 29
A/C switch and A/C relay system
Probable cause
When an A/C ON signal is input to the engine-ECU, the engine-ECU carries out
control of the idle speed control (ISC) servo, and also operates the A/C compressor
magnetic clutch.
D Malfunction of A/C control system
D Malfunction of A/C switch
D Improper connector contact, open or short-circuited
harness wire
D Malfunction of the engine-ECU
Check the A/C compressor relay.
(Refer to GROUP 55 – On-vehicle Service.)
NG
Replace
OK
Measure at the engine-ECU connectors B-59, B-60.
D Disconnect the connector, and measure at the harness side.
D Voltage between 22 and earth, and 45 and earth
(Ignition switch: ON, A/C switch: ON)
OK: System voltage
D Short-circuit between 22 and earth
(Ignition switch: ON, A/C switch: ON)
OK: A/C compressor clutch turns on.
NG
Check the A/C system. (Refer to GROUP 55 – On-vehicle Service.)
OK
Check the following
connectors: B-59, B-60
NG
Replace
OK
Check trouble symptom.
NG
Replace the engine-ECU.
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