Mazda 626 Station Wagon, Workshop Manual

Page: 136 / 577

TROUBLESHOOTING
STEP
INSPECTION RESULTS
ACTION
14
Turn ignition switch on.
Disconnect TP sensor connector.
Measure voltage at TP sensor connector VREF
terminal with ignition switch on.
Voltage
4.5—5.5 V
Is voltage okay?
Yes Go to next step.
No
Go to symptom troubleshooting No.27 “Constant
voltage”.
15 Does engine start with throttle closed? Yes Go to Step 31.
No Go to next step.
16 Will engine start and run smoothly at part
throttle?
Yes
Inspect IAC valve and wiring harness.
No Go to next step.
17 Connect NGS tester to DLC.
Access RPM PID.
Is RPM PID indicating engine speed during
engine cranking?
Yes Go to next step.
No Inspect for following:
• Open or short circuit in CKP sensor
• Open or short circuit between CKP sensor
and PCM terminal 21
• Open or short circuit in CKP sensor
harnesses
If CKP sensor and harness are okay, go to next
step.
18 Visually inspect CKP sensor and teeth of
crankshaft pulley.
Are CKP sensor and teeth of crankshaft pulley
okay?
Yes Go to next step.
No Replace malfunctioning parts.
19 Measure gap between CKP sensor and teeth of
crankshaft pulley.
Specification
0.5—1.5 mm {0.020—0.059 in}
Is gap within specification?
Yes Go to next step.
No
Adjust CKP sensor.
20 Inspect for cracks on high-tension leads.
Is there any crack on high-tension leads? Yes Repair suspected high-tension leads.
No Go to next step.
21 Is strong blue spark visible at each
disconnected high-tension lead while cranking
engine?
Yes Go to next step.
No
Inspect for following:
• Open or short circuit in ignition coi)
• Open circuit in high-tension leads
• Open circuit between ignition coil connector
GND terminal and GND
• Open circuit between ignition switch and
ignition coil
• Open circuit between ignition coil and PCM
terminal 26 or 52
22
Inspect spark plug conditions.
Is spark plug wet, covered with carbon or
grayish white? Yes If spark plug is wet or covered with carbon,
inspect for fuel leakage from injector.
If spark plug is grayish white, inspect for clogged
fuel injector.
No Install spark plugs on original cylinders.
Go to next step.
23 Remove and shake PCV valve. Yes
Go to next step.
Does PCV valve rattle?
No Replace PCV valve.
24
Is there any restriction in exhaust system? Yes Inspect exhaust system.
No Go to next step.
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