Mazda MX-6 1998, Workshop Manual

Page: 217 / 1282

TROUBLESHOOTING [ENGINE CONTROL KL]
DTC No.
Diagnosed Circuit Condition MIL DC*1 OBD Monitor*2
P1765 3 -2 timing control solenoid
Malfunction
c r 0 5 -0 1 B AUTOMATIC TRANSAXLE ON
BOARD DIAGNOSIS [GF4A-EL]
P1780
O/D OFF switch
Circuit malfunction (Open,
short)
tr 0 5 -0 1 B AUTOMATIC TRANSAXLE ON
BOARD DIAGNOSIS [GF4A-EL]
*1 : DC signifies the number of consecutive drive cycles required to illuminate the M IL
*2 : Appropriate OBD II Monitor.
DTC P0102 MAF sensor circuit low input
DESCRIPTION
• Diagnostic Trouble Code (DTC) P0102 indicates MAF signal went below 0.39 volts (refer
to Voltage to Mass Air Flow Conversion Table) sometime during normal engine operation
(Continuous)
[Possible Cause]
• Damaged MAF sensor • MAF circuit shorted to ground
• MAF sensor disconnected • Air Intake Leak (near MAF sensor)
• MAF circuit open • Throttle Position (TP) system (possible closed throttle
• Power circuit open indication)
• Ground circuit open • Damaged PCM
STEP
INSPECTION
ACTION
1
CHECK MAF SIGNAL LOW INPUT TO PCM
• Check broken/loose air outlet tube clamps
(throttle body and air cleaner component
ends), cracks/holes in air outlet tube, worn
gaskets between MAF sensor and air
cleaner component. Service as necessary.
• Start engine and bring to idle.
Note
• If KOER DTC P0505 is present, go to
Diagnostic Trouble Code Charts. If
stabilized idle is not under 700 rpm, go to
ENGINE SYMPTOM
TROUBLESHOOTING.
• Run engine up 1500 rpm for 5 seconds,
then bring it back to idle.
• Access MAF PID with NGS tester.
• Is MAF PID less than specified value?
tr 01—40B MASS AIR FLOW SENSOR
INSPECTION [KL].
Yes MAF sensor signal is not as specified.
Go to next step.
No
For Key on engine running (KOER) reading between
0.60 and 1.00 volt:
Go to step 10.
All others:
Go to step 1 3.
2
CHECK MAF SENSOR POWER CIRCUIT
VOLTAGE
• Key off.
• Disconnect MAF sensor.
• Key on, engine off.
• Measure voltage between power circuit at
MAF sensor vehicle harness connector
and battery negative post.
• Is voltage greater than 10.5 volts?
Yes
Power harness circuit from MAF sensor to battery
negative post okay.
Go to next step.
No
Service open power circuit.
RESET PCM to completely clear DTCs.
tr After Repair Procedure
COMPLETE OBD II Drive Mode.
RETURN OBD Test.
3
CHECK CONTINUITY OF MAF SENSOR
POWER CIRCUIT
• Key off.
• MAF sensor disconnected.
• Disconnect PCM. Inspect for damaged or
pushed out pins, corrosion, loose wires,
etc. Service as necessary.
• Install breakout box. Leave PCM
disconnected.
• Measure resistance between power circuit
at MAF sensor vehicle harness connector
and Test Pin 71 or 97 at breakout box.
• Is resistance less than 5.0 ohms?
Yes Power harness circuit to PCM is okay.
Go to next step.
No Service open power harness circuit.
REMOVE breakout box.
RECONNECT all components.
RESET PCM to completely clear DTCs.
i t
After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
0 1 -0 1 B-11