Mazda B-Series 1997 Workshop Manual page 487

FT
ON-BOARD DIAGNOSIS SYSTEM
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Diagnostic trouble code
1
IDLE AIR CONTROL (IAC) SYSTEM CIRCUIT
No. P1506
I
Symptom
1
Overspeed error detected.
1
I
STEP
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INSPECTION ACTION
1
Inspect the inlet air system with the engine running,
listening for vacuum leaks, and looking for any cracks or
leaks in the system.
Are any leaks detected?
- -
Key OFF.
Disconnect hoses at EVAP canister purge solenoid.
Connect hand vacuum pump to either port and apply
16 in-Hg (53 kPa) of vacuum.
Does solenoid hold vacuum for 20 seconds?
Yes Repa~r or replace components as necessary.
Go to step 7.
-
- -
- -
- -
No Go to next step.
Yes Go to next step.
No Replace EVAP purge solenoid.
Go to step 6.
With the transmission in P (Park) [N (Neutral)] and the
engine running at normal operating temperature, does the
rpm drop or the engine stall when the IAC solenoid is
disconnected?
[
1:
indicates MT models
I
I Yes Go to next step.
lnspect throttle body for damage or defects.
If OK, replace IAC valve.
If not OK, repair or replace throttle body.
Go to step 6.
Key OFF. Disconnect ISC solenoid.
Install breakout box, leave PCM disconnected.
Is the resistance greater than 10,000 ohms between IAC
SIG test pin 83 and PWR GND test pins 511103 at
breakout box?
I
Yes
For fast idle symptom currently present:
Replace PCM.
All others:
Go to step 5.
Repair short in IAC SIG circuit.
Go to steD 6.
Key ON, engine running.
/
i
Monitor the IAC and RPM PlDs with all accessories off.
Yes Repair malfunctioning IAC components as
intermittent faults are identified.
1
Is the IAC PID between 20% and 45% at ~dle, or do the
I
Go to step 6.
--
IAC ' I D and RPM suddenly change during a wigglelta~
'
No
'
For idle quality, starting, or stalling
test, or when snapped?
symptoms currently present:
Replace IAC solenoid.
Go to next step.
TEST PIN 83
TEST PIN 71
6
TEST PIN 97
All others:
Go to "lntermrttent Concerns."
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page FT-69
Perform After Repair Procedure to ensure customer's concern has been resolved.
IDLE AIR
CONTROL
SOLENOID
CONNECTOR
WILE IAC SIG
' "
vpw
(VIEW FROM PIN SIDE)
MF1863-C
FROM POWER
RELAY