Mazda 626 Station Wagon, Workshop Manual

Page: 142 / 577

TROUBLESHOOTING
STEP INSPECTION
RESULTS
ACTION
4 Does idle speed drop or stall when Yes Go to next step.
disconnecting IAC valve?
No Inspect following:
• Circuit from IAC valve to PCM connector
terminal 20 (for GF4A-EL models)/54 (except
for GF4A-EL models) or 83 for open and
short
• IAC valve for being stuck
If okay, go to next step.
5 Disconnect vacuum hose between purge
solenoid valve and intake manifold from purge
solenoid valve side.
Yes Inspect evaporative emission control system.
Plug opening end of vacuum hose.
Drive vehicle.
Does engine condition improve?
No Go to next step.
6 Connect NGS tester to DLC.
Access TP V, MAF V, VS, BRK SW, TR SW
(ATX) and NL SW (MTX) PIDs.
Monitor each PID while driving vehicle.
Except for GF4A-EL models
• TP V PID
• MAF V PID
• VS PID
• BRK SW PID
Yes Go to symptom troubleshooting 26 for
“Intermittent concerns”.
• TR SW PID
• NL SW PID
For GF4A-EL models
• TP V PID
• MAF V PID
• VSS PID
• BOO PID
• TR PID
• CPP/PNP PID
Are PIDs okay?
(See F1-25 PCM INSPECTION (except for
GF4A-EL models))
(See Section F (for GF4A-EL models))
No TP V PID: Inspect TP sensor.
MAF V (MAF) PID: Inspect MAF sensor.
VS (VSS) PID: Inspect VSS.
BRK SW (BOO) PID: Inspect brake switch.
TR SW (TR) PID: Inspect TR switch.
NL SW (CPP/PNP) PID: Inspect neutral switch.
7
Verify test results. If okay, return to diagnostic index to service any additional symptoms.
| N010. ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE,
' SURGES
10
Engine stalls/quits - accelaration/cruise
Engine runs rough - accelaration/cruise
Misses - acceleration/cruise
Buck/Jerk - acceleration/crulse/deceleration
Hesitation/stumble - acceleration
Surges - acceleration/cruise
DESCRIPTION
• Engine stops unexpectedly at beginning of acceleration or during acceleration.
• Engine stops unexpectedly while cruising.
• Engine speed fluctuates during acceleration or cruising.
• Engine misses during acceleration or cruising.
• Vehicle bucks/jerks during acceleration, cruising or deceleration.
• Momentary pause at beginning of acceleration or during acceleration.
• Momentary minor irregularity in engine output.
F1-121