Mazda 6 2002, Workshop Manual

Page: 227 / 1248

F–98
ON-BOARD DIAGNOSTIC
DTC P0121
A6E397001084W18
Diagnostic procedure
DTC P0121 Throttle position stuck close (lower than expected)/open (higher than expected)
DETECTION
CONDITION
•
If PCM detects that throttle valve opening angle is below 12.5% for 5 s after following conditions are met,
PCM determines that TP is stuck closed:
MONITORING CONDITION
— Engine coolant temperature above 80
°
C {176
°
F}
— MAF sensor signal above 32.0 g/s {4.2 lb/minutes}
•
If PCM detects that throttle valve opening angle is above 50% for 5 seconds after following conditions are
met, the PCM determines that TP is stuck open:
MONITORING CONDITION
— Engine speed above 500 rpm
— MAF sensor signal 5 g/s {0.7 lb/min.}
Diagnostic support note
•
This is a continuous monitor (CCM).
•
MIL illuminates if PCM detects the above malfunction condition in two consecutive drive cycles or in one
drive cycle while the DTC for the same malfunction has been stored in the PCM.
•
PENDING CODE is available if PCM detects the above malfunction condition.
•
FREEZE FRAME DATA is available.
•
DTC is stored in the PCM memory.
POSSIBLE
CAUSE
•
TP sensor malfunction
•
Electrical corrosion in TP signal circuit
•
Voltage drops in constant voltage supply circuit
•
Voltage drops in ground circuit
•
MAF sensor malfunction
•
PCM malfunction
STEP INSPECTION ACTION
1 VERIFY FREEZE FRAME DATA HAS BEEN
RECORDED
•
Has FREEZE FRAME DATA been recorded?
Yes Go to next step.
No Record FREEZE FRAME DATA on repair order, then go to
next step.
2 VERIFY RELATED PENDING CODE OR
STORED DTC
•
Turn ignition key to ON (Engine OFF).
•
Retrieve pending or stored DTC using WDS or
equivalent.
•
Is DTC P0101 also retrieved?
Yes Go to DTC P0101 troubleshooting procedure.
No Go to next step.
3 VERIFY RELATED SERVICE INFORMATION
AVAILABILITY
•
Check for related Service Information
availability.
•
Is any related Service Information available?
Yes Perform repair or diagnosis according to available Service
Information.
•
If vehicle is not repaired, go to next step.
No Go to next step.
4 VERIFY CURRENT INPUT SIGNAL STATUS - IS
CONCERN INTERMITTENT OR CONSTANT
•
Start the engine.
•
Access ECT, TP and MAF PIDs using WDS or
equivalent.
•
Warm up the engine until ECT PID is above 80
°
C {176
°
F}
•
Drive the vehicle.
•
Read TP PID while MAF PID is above 32.0 g/s
{4.2 lb/min.} .
•
Is TP PID reading above 12.5% ?
Yes Go to Step 7.
No Go to next step.
5 VERIFY TP PID
•
Start engine.
•
Access TP, MAF and RPM PIDs using WDS or
equivalent.
•
Read TP PID while MAF PID is below 4.8 g/s
{0.6 lb/min.} and RPM PID is above 500 rpm .
•
Is TP PID reading above 50% ?
Yes Go to Step 12.
No Go to next step.