Engine General Information and Diagnosis: 1A-147
DTC Troubleshooting
NOTE
• 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”.
• Upon completion of inspection and repair work, perform “DTC Confirmation Procedure” and
confirm that the trouble has been corrected.
Step Action Yes No
1 Was “Engine and Emission Control System Check”
performed?
Go to Step 2. Go to “Engine and
Emission Control
System Check”.
2 Control module connector check
1) Check connection of connectors of all control module/
sensor communicating by means of CAN.
2) Recheck DTC.
Is DTC P1674 detected?
Go to Step 3. Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
3 CAN communication circuit check
1) Turn ignition switch to OFF position.
2) Disconnect connectors of all control module/sensor
communicating by means of CAN.
3) Check CAN communication circuit between control
module/sensor for open, short and high resistance.
Is each CAN communication circuit in good condition?
Go to Step 4. Repair circuit.
4 DTC check of ECM
1) Turn ignition switch to OFF position.
2) Connect connectors of disconnected control module/
sensor communicating by means of CAN.
3) Disconnect connector from any one of control module/
sensor other than BCM and ECM.
4) Recheck ECM for DTC.
Is DTC P1674 detected?
Disconnect connectors
of control module/
sensor other than the
one whose connector is
disconnected in Step 3)
one by one and check
that DTC P1674 is
detected by ECM each
time connector is
disconnected. When
DTC P1674 is not
detected by ECM while
checking in this way, go
to description under
“NO” below. If DTC
P1674 is detected by
ECM, go to Step 5.
Check power and
ground circuit of control
module disconnect in
Step 3). If circuit is OK,
substitute a known-
good control module
disconnected in Step 3)
and recheck.
5 DTC check of ECM
1) Substitute a known-good BCM and recheck ECM for
DTC.
Is DTC P1674 detected?
Substitute a known-
good ECM and recheck.
End.