Mazda 626 Station Wagon, Workshop Manual

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ON-BOARD DIAGNOSTIC
D T C P 1170
Except for G F4A -EL Models
DTC P1170
H02S no inversion
DETECTION
CONDITION
• PCM monitors input voltage from H02S when following monitoring conditions are met. If input voltage
from sensor is below or above 0.55 V for 30.4 seconds, PCM determines that there is no H02S
inversion.
MONITORING CONDITIONS
• Engine speed is above 1,500 rpm.
• Engine coolant temperature is above 80 °C {176 ” F}.
POSSIBLE
CAUSE
• H02S malfunction
• Fuel injector malfunction
• Pressure regulator malfunction
• Fuel pump malfunction
• Clog or leakage from following fuel line
— Between fuel tank and fuel distributor.
— Between pressure regulator and fuel tank
• Air suction or leakage from intake air system
• Purge solenoid valve malfunction
• Insufficient compression
Diagnostic procedure
STEP INSPECTION
ACTION
1 VERIFY RELATED REPAIR INFORMATION
AVAILABILITY
• Check for related Service Information
availability.
• Is any related Service Information available?
Yes Perform repair or diagnosis according to available
Sen/ice Information.
• If vehicle is not repaired, then go to next step.
No Go to next step.
2 CLASSIFY INTERMITTENT CONCERN OR
CONTINUOUS CONCERN
• Turn ignition key to ON (Engine OFF).
• Clear DTC from memory using NGS tester.
• Perform following procedure twice.
— Start engine
— Access ECT and RPM PIDs using NGS
tester.
— Make sure that ECT PID is above 80 “C
{176 ’ F}
— Increase and keep engine speed above
1,500 rpm for at least 20.4 seconds.
• Is another DTC present?
Yes Go to appropriate DTC troubleshooting procedures.
No Go to next step.
3 IDENTIFY TRIGGER DTC
• Is DTC P1170 present?
Yes Go to next step.
No Intermittent concern is existing. Go to
INTERMITTENT CONCERN TROUBLESHOOTING
procedure.
(See F1-142 N0.26 INTERMITTENT CONCERNS
TROUBLESHOOTING)
4
INSPECT H02S OUTPUT VOLTAGE
• Start engine
• Access FH02S PID using NGS tester.
• Is FH02S PID value goes up and down at
over 0.55 V?
Yes Malfunction not by H02S circuit. Go to Step 6.
No Malfunction by H02S circuit. Go to next step.
5 INSPECT H02S CIRCUIT
• Inspect following circuit for open or short.
— Between H02S terminal A (harness-side)
and PCM terminal 60 (harness-side)
— Between H02S terminal B (harness-side)
and PCM terminal 91 (harness-side)
— Between H02S terminal C (harness-side)
and battery positive voltage.
— Between H02S terminal D (harness-side)
and PCM terminal 94 (harness-side)
• Are there any malfunctions?
Yes
Repair or replace appropriate wiring harness, then go
to Step 13.
No Replace appropriate H02S, then go to Step 13.
F1-66