Engine General Information and Diagnosis: 1A-246
Troubleshooting
NOTE
• Before performed troubleshooting, be sure to read the “Precautions of ECM Circuit Inspection: ”.
• When measuring circuit voltage, resistance and/or pulse signal at ECM connector, connect the
special tool to ECM and/or the ECM connectors referring to “Inspection of ECM and Its Circuits: ”.
• When A/C evaporator outlet air temp. is below 0
°
C (32
°
F) (for J20 engine) or 1.3
°
C (34.3
°
F) (for
M16 engine), A/C remains OFF (“E23-49” terminal voltage becomes 10 – 14 V). This condition is not
abnormal.
Step
Action
Yes
No
1
Reception data check from BCM
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Turn ON ignition switch.
3) Check DTC for reception data from BCM.
Is there DTC P1678?
Go to applicable DTC
diag. flow.
Go to Step 2.
2
DTC check of HVAC control module
1) Check HVAC control module for DTC.
Is there DTC(s)?
Go to applicable DTC
diag. flow.
Go to Step 3.
3
A/C switch signal circuit check
1) Start engine and select “DATA LIST” mode on scan tool.
2) Check A/C switch signal under following conditions
respectively.
A/C switch signal
Engine running, A/C switch OFF: OFF
Engine running, A/C switch ON and blower speed
selector turned 1st position or more: ON
Is check result satisfactory?
Go to Step 4.
Check HVAC control
module and its circuit.
4
DTC check of ECT sensor circuit
1) Check ECM for DTC of ECT sensor circuit.
Is there DTC P0116, DTC P0117 or DTC P0118?
Go to applicable DTC
diag. flow.
Go to Step 5.
5
Radiator cooling fan control system check
Is radiator cooling fan started when A/C and blower speed
selector switch are turned ON with engine running?
Go to Step 11.
Go to Step 6.
6
Radiator cooling fan control circuit check
1) Check DTC with scan tool.
Is DTC P0480 displayed?
Go to “DTC P0480: Fan
1 (Radiator Cooling
Fan) Control Circuit: ”.
Go to Step 7.
7
Evaporator temperature sensor check
1) Check evaporator temperature sensor referring to “A/C
Evaporator Temperature Sensor Inspection: in Section
7B”.
Is resistance within specification?
Go to Step 8.
Faulty evaporator
temperature sensor.
8
DTC check of A/C refrigerant pressure sensor circuit
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Turn ON ignition switch.
3) Check ECM for DTC of A/C refrigerant pressure sensor
circuit.
Is there DTC P0532 or DTC P0533?
Go to applicable DTC
diag. flow.
Go to Step 9.
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