Engine Electrical System

Diagnostic trouble code: P0122 “Undervoltage in circuit for throttle position
sensor”
Item
No.
Operation procedure
Inspection
results
Follow-up
procedure
1
Connect the diagnostic tester and adaptor,
and turn the ignition switch to “ON”
position.
Proceed to next
step.
Yes
Proceed to next
step.
2
Observe the item of “throttle absolute
opening” in the data flow to verify that the
value is maintained within 4%-10% (the
exact value varies from individual auto
model.)
No Proceed to Step5
Yes
Proceed to next
step.
3
Step on the accelerator pedal slowly until
full opening, observe the “absolute
opening of throttle” in data flow and verify
that the value is increased to 85%-95%
with the increasing of the accelerator pedal
opening (the exact value varies from
individual auto model).
No Proceed to Step 5
Yes Replace the sensor.
4
Repeat the step 3, observe the “absolute
opening of throttle” in data flow to verify
that there is jump during the change of the
value.
No
Proceed to next
step.
Yes
Repair and replace
the wiring harness.
5
Disconnect the connector of the throttle
position sensor on the wiring harness to
verify that the circuits between 17#, 32#,
and 16# pins of ECU and 1#, 2#, and 3#
pins of the sensor connector are short to
ground.
No
Proceed to next
step.
Yes Replace the sensor.
6
Inspect with multimeter to verify that the
voltage between 1# and 2# pins of this
connector is about 5V.
No
Refer to diagnosis
help.
E-26
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