
Maintenance Manual for J2 Sedan
Electronic Control System
of Engine
211
Fault code: P0122 “the circuit voltage of throttle position sensor is at the extremely low limit”
S/N
Step
Check result
Subsequent step
1
Connect the diagnosis device and adapter, and turn the ignition switch
to ON position.
Next step
Yes
Next step
2
Observe if the value of “Throttle opening” is between 4% and 10%
(depending on the bus model).
No
To Step 5
Yes
Next step
3
Slowly depress the accelerator pedal to fully open the throttle, and
observe if the value of “Throttle opening” in the data flow increases
to 85-95% along with the increase of throttle opening (depending on
the bus model).
No
To Step 5
Yes
Replace the
sensor
4
Repeat Step 3 and observe if the value of “Throttle opening” in the
data flow springs during change.
No
Next step
Yes
Repair or replace
the harness
5
Unplug the connector of throttle position sensor on the harness, and
check if the circuits connecting Pins 39#, 18# and 26# of ECU
respectively to Pins 1#, 2# and 3# of sensor connector are short to
ground.
No
Next step
Yes
Replace the
sensor
6
Check if the voltage between Pins 1# and 2# of this connector is
about 5V by the multimeter.
No
Diagnosis help
Fault code: P0123 “the circuit voltage of throttle position sensor is at the extremely high limit”
S/N
Step
Check result
Subsequent step
1
Connect the diagnosis device and adapter, and turn the ignition switch
to ON position.
Next step
Yes
Next step
2
Observe if the value of “Throttle opening” is between 4% and 10%
(depending on the bus model).
No
To Step 5
Yes
Next step
3
Slowly depress the accelerator pedal to fully open the throttle, and
observe if the value of “Throttle opening” in the data flow increases
to 85-95% along with the increase of throttle opening (depending on
the bus model).
No
To Step 5
Yes
Replace the
sensor
4
Repeat Step 3 and observe if the value of “Throttle opening” in the
data flow springs during change.
No
Next step
Yes
Repair or replace
the harness
5
Unplug the connector of throttle position sensor on the harness, and
check if the circuits connecting Pins 39#, 18# and 26# of ECU
respectively to Pins 1#, 2# and 3# of sensor connector are open or
short to power source.
No
Next step
Yes
Replace the
sensor
6
Check if the voltage between Pins 1# and 2# of this connector is
about 5V by the multimeter.
No
Diagnosis help