Upstream Heated Oxygen Sensor - Mazda B-Series 1997 Workshop Manual

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ON-BOARD DIAGNOSIS SYSTEM
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Diagnostic trouble code
1
DTC P1128: UPSTREAM HEATED OXYGEN SENSOR
No. PI128
STEP
Symptom
1
Upstream H02S signal(s) are swapped from bank to bank during KOER self-test.
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INSPECTION ACTION
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Key OFF. Repair as necessary.
Visually inspect HO2S vehicle connector for stretched
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GO to step 3.
wires or improper mounting.
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Are there any indications of crossed connections or wires?
No G o t o p s t e p .
Key OFF.
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Yes
Install breakout box, leave PCM d~sconnected.
Disconnect suspect H02S connector.
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For DTC P1128: H02S 11/21 for upstream H02S.
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Measure resistance between H02S SIG test p ~ n at
No
breakout box and H02S vehicle connector.
- H02S-11: Test pin 60
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H02S-21: Test pln 87
Is resistance less than 5.0 ohms?
Go to next step.
Repair open circuit in H02S SIG.
Go to next step.
Perform After Repair Procedure to ensure customer's concern has been resolved.
HEATED OXYGEN SENSOR
CONNECTOR (H02S)
HEATER
GROUND
VPWR
(HTR GND)
H02S SIG SIG RTN
'TEST PINS LOCATED ON
BREAKOUT BOX
(VIEW FROM PIN SIDE)
H02S LOCATION
ENGINE
(6 CYL)
ENGINE