Mazda 3 Workshop Manual page 108

Mazda 3 Workshop Manual – Engine + Wiring Diagrams + Diagnostic Trouble Codes
VERIFY CURRENT INPUT SIGNAL
STATUS
• Warm up the engine.
• Access O2S11 PID using the WDS or
equivalent.
• Verify PID while racing engine (in NEUTRAL
(MTX) or PARK (ATX)).
• Is PID normal?
- More than 0.55 V when suddenly
depressing the accelerator pedal (rich
condition)
- Less than 0.55 V just after
releasing the accelerator pedal (lean
condition)
INSPECT INSTALLATION OF FRONT HO2S
• Inspect if the front HO2S is loosely installed.
5
• Is sensor installed securely?
INSPECT GAS LEAKAGE FROM EXHAUST
SYSTEM
• Visually inspect if there is any gas leakage
6
between the exhaust manifold and the front
HO2S.
• Is there gas leakage?
INSPECT SEALING OF ENGINE COOLANT
PASSAGE
Warning
• Removing the radiator cap when the
radiator is hot is dangerous. Scalding
7
coolant and steam may shoot out and
cause serious injury.
• When removing the radiator cap,
wrap a thick cloth around and turn it
slowly.
• Remove the radiator cap.
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No Go to the next step.
Yes Go to the next step.
Install sensor securely, then go to Step 9.
No
(See FRONT HEATED OXYGEN SENSOR
(HO2S) REMOVAL/INSTALLATION
Repair or replace any malfunctioning
Yes
exhaust part, then go to Step 9.
• Inspect the following wiring harnesses for
open circuit or short to GND in wiring
harness.
- Front HO2S terminal A (wiring
harness-side) to PCM terminal 2AI
(wiring harness-side)
No
• Repair or replace wiring harness if
necessary.
• If all items above are normal, replace the
malfunctioning sensor.
Then go to Step 9.
Air gets in from poor sealing on head gasket
or other areas between combustion chamber
and engine coolant passage.
Yes
Repair or replace the malfunctioning part,
then go to Step 9.
No Go to the next step.
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