Mazda 6 2002, Workshop Manual

Page: 228 / 1248

ON-BOARD DIAGNOSTIC
F–99
F
6 VERIFY CURRENT INPUT SIGNAL STATUS - IS
CONCERN INTERMITTENT OR CONSTANT
•
Drive the vehicle and read MAF PID.
•
Does MAF PID change in compliance with
driving condition?
Yes Intermittent concern exists. Go to INTERMITTENT
CONCERNS troubleshooting procedure.
No Inspect Mass airflow sensor and related circuits and
terminals.
(See
F–51 MASS AIR FLOW (MAF) SENSOR
INSPECTION .)
Repair or replace as necessary, then go to Step 16.
7 INSPECT TP SENSOR TERMINALS FOR
ELECTRICAL CORROSION
•
Turn ignition key to OFF.
•
Disconnect TP sensor connector
•
Inspect for electrical corrosion on male and
female TP sensor terminals.
•
Is any electrical corrosion found?
Yes Repair or replace suspected terminal or TP sensor, then go
to Step 11.
No Go to next step.
8 VERIFY TP SENSOR
•
Does TP sensor resistance smoothly change
while gradually opening throttle valve?
Yes Go to next step.
No Replace TP sensor, then go to Step 11.
9 INSPECT PCM TERMINALS FOR ELECTRICAL
CORROSION
•
Disconnect PCM connector.
•
Inspect for electrical corrosion on PCM male
and female terminals.
•
Is any electrical corrosion found?
Yes Repair terminal, then go to Step 11.
No Go to next step.
10 INSPECT CONSTANT VOLTAGE SUPPLY AND
TP SIGNAL CIRCUITS FOR VOLTAGE DROP
•
Turn ignition key to ON (Engine OFF).
•
Inspect voltage between following terminals:
— TP sensor connector terminal C (harness-
side) and PCM terminal 2K
— TP sensor connector terminal B (harness-
side) and PCM terminal 2A
•
Is voltage approx. 0 V ?
Yes Go to next step.
No Inspect for rust or corrosion on PCM terminals 2A and 2K
(harness-side).
•
Repair or replace suspected terminal then go to next
step.
11 VERIFY TROUBLESHOOTING OF DTC P0121
COMPLETED
•
Make sure to reconnect all disconnected
connectors.
•
Start the engine.
•
Clear DTC from PCM memory using WDS or
equivalent.
•
Access ECT, TP and MAF PIDs using WDS or
equivalent.
•
Warm up the engine until ECT PID is reading
above 80
°
C {176
°
F} .
•
Drive the vehicle and read TP and MAF PIDs.
•
Verify PIDs reading are within specifications
MAF PID:
above 32.0 g/s {4.2 lb/min.}
TP PID: above 12.5% above 5 s
•
Is PENDING CODE of same DTC present?
Yes Replace PCM, then go to Step 17.
No Go to Step 17.
12 INSPECT TP SENSOR TERMINALS FOR
ELECTRICAL CORROSION
•
Turn ignition key to OFF.
•
Disconnect TP sensor connector.
•
Inspect for electrical corrosion on male and
female TP sensor terminals.
•
Is any electrical corrosion found?
Yes Repair or replace suspected terminal or TP sensor, then go
to Step 16.
No Go to next step.
13 INSPECT GROUND CIRCUIT FOR VOLTAGE
DROP
•
Inspect resistance between TP sensor terminal
A (harness-side) and body ground.
•
Is resistance approx. 0 ohm ?
Yes Go to next step.
No Repair or replace for rust or corrosion on PCM terminal 2H
(harness-side).
•
Repair or replace suspected terminal.
Go to Step 16.
14 VERIFY TP SENSOR
•
Does resistance smoothly change while
gradually opening throttle valve?
Yes Go to next step.
No Replace TP sensor, then go to Step 16.
STEP INSPECTION ACTION