Mazda MX-6 1998, Workshop Manual

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TROUBLESHOOTING [ENGINE CONTROL FS]
STEP INSPECTION ACTION
10 Are KOEO DTCs present for two or more
sensors connected to ground circuit?
Sensors connected to ground:
EGR boost sensor, TP sensor, IAT sensor,
ECT sensor, FTP sensor, TR sensor,
H 0 2 S -1 1, H 0 2 S -1 2 , clutch switch, PSP
switch, TFT sensor.
Yes Go to next step.
No
Repair open ground circuit to sensor where constant
voltage circuit check failed.
11 Key off.
Disconnect NGS tester from DLC.
Disconnect sensor connector where constant
voltage circuit check failed.
Install breakout box. Leave PCM
disconnected.
Measure resistance between ground circuit at
appropriate sensor connector and ground Test
Pin 91 at breakout box.
Is resistance less than 5.0 ohms?
Yes Reconnect sensor connector.
Go to next step.
No
Repair open ground circuit.
12 Key off.
Disconnect NGS tester from DLC.
Install breakout box. Leave PCM
disconnected.
Measure resistance between battery negative
terminal and ground Test Pins 51/76/77/103 at
breakout box.
Is each resistance less than 5.0 ohms?
Yes Go to next step.
No Repair open ground circuit to ground.
13 Key off.
Connect PCM to breakout box.
Measure resistance between PCM ground
test pin 91 and ground Test Pins 51/76/77/103
at breakout box.
Is each resistance less than 5.0 ohms?
Yes Ground circuits are okay.
No Replace PCM.
14 Key off.
Disconnect sensor connector where constant
voltage check failed.
Disconnect TP fuel tank pressure sensor and
EGR boost sensor connectors.
Disconnect PCM connector.
Key on, engine off.
Measure voltage between constant voltage
circuit at TP sensor connector and battery
negative terminal.
Is voltage less than 0.5 volts?
Yes Replace PCM.
No
Repair constant voltage circuit short to power in harness.
0 1 -0 1 A - 1 68