Mazda B-Series 1997 Workshop Manual page 428

ON-BOARD DIAGNOSIS SYSTEM
FT
Yes
No
Yes
- -
No
I
STEP
!
INSPECTION
Go to next step.
ACTION
Key OFF.
Disconnect MAF sensor.
Key ON, engine off.
Is voltage between VPWR (R) circuit at MAF sensor
connector and battery negative terminal greater than 10.5
volts?
Repair open in VPWR circuit.
Go to step 21.
- ----
Go to next step.
Key OFF.
Leave PCM and MAF disconnected.
Is resistance between VPWR (R) circuit at MAF sensor
connector and VPWR test pin 7 1 or 97 at breakout box
less than 5 . 0 ohms?
Repair open in VPWR circuit.
Go to step 21.
Key OFF.
Leave PCM and MAF disconnected.
Disconnect scan tool or NGS from data link connector.
Measure the resistance between MAF SIG test pin 88 and
MAF RTN test pin 36 and PWR GND test pins 24 or 103
at the breakout box.
Is each resistance areater than
10,000
ohms?
Go to next step.
Repair short circuit between MAF SIG and
GROUND or MAF RTN.
Go to step 21.
Key OFF.
Leave PCM and MAF disconnected.
Is resistance between MAF SIG (LBIR) at MAF sensor
connector and MAF SIG test pin 88 at breakout box less
Go to step
21.
than 5.0 ohms?
Key OFF.
Leave MAF sensor disconnected.
Reconnect PCM to breakout box.
Key ON, engine off.
Is
the voltage between VPWR (R) and PWR GND
(B)
circuit at MAF sensor connector areater than
10.5
volts?
1
Yes
/
GO to step I 3.
Go to next step.
I
Key OFF.
Leave MAF and scan tool or NGS disconnected.
Disconnect PCM.
Is the resistance between PWR GND (B) circuit at MAF
sensor connector and battery negative terminal less than
10.0 ohms?
No
1
Repair open in PWR GND circuit.
1
GO to step 21.
1
i
Key OFF.
Leave MAF sensor disconnected.
Disconnect PCM.
Is the resistance between MAF RTN (TtLB) circuit at MAF
sensor connector and MAF RTN test pin
36
at breakout
box less than 5.0 ohms?
Yes
j
Go to next step.
No Repair open in MAF RTN circuit.
Go to step
21.
I
l 4
1
Key OFF.
1
Yes Go to next step.
Leave MAF and scan tool or NGS disconnected.
Reconnect PCM to breakout box.
Measure resistance between MAF SIG test pin 88 and
MAF RTN test pin 36 and PWR GND test pin 24 or 103 at
the breakout box.
Is each resistance areater than
10,000
ohms?
No
/
MAF SIG shorted to PWR GND or MAF RTN
,
in PCM. Replace PCM.
,
Go to step
21.
Key OFF.
Connect MAF sensor connector.
Install breakout box and reconnect PCM.
Key ON, engine running.
Note: If a stabilized idle is not at least 700 rpm, go to
Diagnostic Index.
For 2.3L AIR If vehicle stalls and cannot maintain idle,
replace
PCM.
Is the voltage between MAF SIG test pin
88
at breakout
box and battery negative terminal at idle between 0.34 and
1.96 volts?
Key ON, engine running.
Measure voltage between MAF SIG test pin 88 and MAF
RTN test pin 36 at breakout box.
Is voltage between
0.34 and 1.96
volts?
Yes Go to next step.
No
MAF SIG or PWR GND is open in MAF
sensor, or MAF SIG is shorted to MAF RTN in
MAF sensor. Replace NlAF sensor.
Go to step 21.
e Go to next step.
MAF RTN open in MAF sensor.
Replace MAF sensor.
Go to ster, 21.