Open circuit in wiring
harness between main
relay and PCM terminal
1AW or 1BE
Open main relay GND
circuit
Main relay is stuck open.
Open or short circuit in
wiring harness between
DLC and PCM terminals
1AM or 1AI
Open or poor GND circuit
(PCM terminal 1AZ,
1BB, 1BD, 1BH)
Poor connection of
vehicle body GND
No
No DTC is displayed:
Go to the next step.
12
Attempt to start engine
at part throttle.
Does engine run
smoothly at part
throttle?
Yes
Inspect electronic throttle
control system operation. (See
ELECTRONIC THROTTLE
CONTROL SYSTEM
INSPECTION
.)
No
Go to the next step.
13
Connect the M-MDS or
equivalent to the DLC-
2. Access RPM PID.
Is RPM PID indicating
engine speed during
engine cranking?
Yes
Go to the next step.
No
Inspect for the following:
Open or short circuit in
CKP sensor
Open or short circuit in
wiring harness between
CKP sensor terminal A
and PCM terminal 2AB
Open or short circuit in
wiring harness between
CKP sensor terminal B
and PCM terminal 2W
Open or short circuit in
wiring harness between
CKP sensor terminal C
and PCM terminal 2AQ
Open or short circuit in
CKP sensor wiring
harnesses
2007 Mazda MX-5 Miata Sport
2007 ENGINE PERFORMANCE Symptom Troubleshooting - MX-5 Miata
Microsoft
Thursday, July 09, 2009 2:42:09 PM
Page 32
© 2005 Mitchell Repair Information Company, LLC.