Idle Air Control (Iac) System Circuit - Mazda B-Series 1997 Workshop Manual

FT
ON-BOARD DIAGNOSIS SYSTEM
1
System at adaptive clip.
INSPECTION
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ACTION
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Diagnostic trouble code
NO.
P I 505
Inspect the inlet air system for any vacuum leaks, plugged
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Go to next step.
air filter, loose throttle body connection, or contaminated or
damaged IAC valve assembly.
Repair or replace components as necessary.
Is the inlet air system OK?
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Go tostep 11.
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Do the throttle body linkage, accelerator cable, and speed
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Yes
:
Go to next step.
IDLE AIR CONTROL (IAC) SYSTEM CIRCUIT
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control cable travel freely-when exercised individually w~th
the accelerator cable and speed control cable
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NO
If cables stick or bind. repair or replace
disconnected^
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cables.
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G o t o s t e ~ l l .
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If cables are OK, ao to steo 6.
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Key ON, engine off. Yes
Access TP PID.
Slowly move throttle from closed to wide open throttle
position and observe TP PID for smooth reading change.
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Release throttle and allow to return to fully closed position.
No
Is TP PID reading between 13% (0.66 volts) and 240h
(1.20 volts) at closed throttle position?
Leave cables disconnected from throttle body linkage.
Verify that throttle return screw is in contact with throttle
linkage lever arm when throttle is in closed-plate position.
Does throttle return screw contact lever arm?
Go to next step.
- -
- -
Adjust screw position.
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page
FT-146
Go to next step.
Go to next step.
Yes
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Check TP sensor.
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Remove cables from throttle body.
Does throttle rotate freely without sticking, binding or
grabbing condition?
Key ON.
Monitor the RPM and IAC PlDs with transmission in P
(Park) [N (Neutral)], the engine running at normal
operating temperature with cooling fan off, and all
accessories off.
Are the IAC PID and RPM PID as follows?
RPM PID IAC PID
2.3L MT 695-745 rprn 20-45%
AT 743-793 ipm 20-44%
3.OL MT 825-875 rprn 20-44%
AT 875-925 rprn 20-44OlO
4.OL MT 725-775 rprn 20-45%
AT 799-849 rprn 20-44%
,
Yes Go to "Dlagnostic Flow Chart."
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GO
to step 9.
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Go to next step.
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r~
,
Go to step 8.
With transmission in P (Park) [N (Neutral)], the engine Yes Go to next step.
running at normal operating temperature with cooling fan
off, and all accessories off:
~
Does the engine stall or does the rprn fluctuate
excessively before returning to normal idle when the
throttle is snapped?
[
1:
indicates MT models
With transmission in P (Park) [N (Neutral)], the engine
Yes
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If fast idle symptom:
running at normal operating temperature with cooling fan 1
Go to step 10.
off, and all accessories off:
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If not fast idle symptom:
Does the rpm drop or does the engine stall when the IAC
GO to next step.
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No Air intake system OK
-
return to Diagnostic
solenoid is disconnected?
[
1:
indicates MT models
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Index to check other driveability symptoms.
No Replace IAC solenold.
Note: Do not attempt to clean IAC.
Go tostep 11.