28 - DTC-Based Diagnostics / MODULE, Powertrain Control (PCM), NGC / Diagnosis and Testing
P0123-THROTTLE POSITION SENSOR 1 CIRCUIT HIGH - 3.3/3.8L
Special Tools: Click to display a list of tools used in this procedure
MODULE-
POWERTRAIN
ETC TP ETC CONTROL
MOTOR 5 VOLT SENSOR MOTOR TP TP
(+) SUPPLY GROUND (-) SIGNAL 2 SIGNAL 1
6 C2 29 C2 15 C2 38 C2 28 C2 21 C2
K855
18
PK/YL
4.0L 3.3L/3.8L
4.0L 3.3L/3.8L
K124 K922 K126 K122 K122 K22
S115 S126
18 18 18 18 18 18
DB/GY BR/DB DB/LG BR/DG DB/GY BR/OR
K855
20
PK/YL
3 6 5 4 1
1 2 3 4 5 6
THROTTLE
ETC 5 VOLT TP ETC TP TP
BODY
MOTOR SUPPLY SENSOR MOTOR SIGNAL 2 SIGNAL 1
(+) GROUND (-)
4.0L
BLACK/ORANGE
10 1
19 11 1 3 2 6
28 20 1 5
4 6
38 29
THROTTLE THROTTLE
BODY BODY
(3.3L/3.8L) (4.0L)
MODULE-
POWERTRAIN
CONTROL C2
01178736
For a complete wiring diagram, refer to the Wiring Information.
When Monitored:
With the engine running and battery voltage greater than 10 volts.
Set Condition:
The Powertrain Control Module (PCM) detects that the sensor input voltage is above the maximum acceptable
value.
Possible Causes
(K855) 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
(K22) TP SIGNAL 1 CIRCUIT SHORTED TO VOLTAGE
(K22) TP SIGNAL 1 CIRCUIT SHORTED TO THE (K855) 5-VOLT SUPPLY CIRCUIT
(K22) TP SIGNAL 1 CIRCUIT SHORTED TO THE (K124) ETC MOTOR (+) CIRCUIT
(K22) TP SIGNAL 1 CIRCUIT SHORTED TO THE (K126) ETC MOTOR (-) CIRCUIT
(K22) TP SIGNAL 1 CIRCUIT OPEN
(K922) TP SENSOR GROUND CIRCUIT OPEN
THROTTLE BODY
POWERTRAIN CONTROL MODULE (PCM)
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based
Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
1.DTC IS ACTIVE
NOTE: Diagnose and repair any APP Sensor circuit, Throttle Body circuit, system voltage, or sensor supply
voltage DTCs before continuing with this test.
1. Start the engine and allow it to reach operating temperature.
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near
the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result
in possible serious or fatal injury.
2. With the scan tool select View DTCs.
NOTE: It may be necessary to test drive the vehicle in order for this DTC to reset.
Is the status Active for this DTC?
Yes
Go To 2
No
Perform the CHECKING FOR AN INTERMITTENT DTC diagnostic procedure. (Refer to 28 - DTC-Based
Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
2.(K855) 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Throttle Body connector. V
3. Disconnect the C2 Powertrain Control Module (PCM) 3
2
harness connector. 1 2
4. Turn the ignition on. 2 BLACK
0
5. Measure the voltage of the (K855) 5-volt Supply circuit in
the Throttle Body harness connector.
1 3
4 6
Is there any voltage present?
Yes THROTTLE
BODY
(3.8L)
Repair the short to voltage in the (K855) 5-volt Supply
circuit. 75095
Perform the PCM VERIFICATION TEST. (Refer to 28 -
DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
No
Go To 3
3.(K22) TP SIGNAL 1 CIRCUIT SHORTED TO VOLTAGE
1. Measure the voltage of the (K22) TP Signal 1 circuit in the
Throttle Body harness connector.
Is there any voltage present?
Yes
Repair the short to voltage in the (K22) TP Signal 1
circuit.
Perform the PCM VERIFICATION TEST. (Refer to 28 -
DTC-Based Diagnostics/MODULE, Powertrain Control
(PCM) - Standard Procedure).
V
No 3
2
1 2
Go To 4
6 BLACK
0
1 3
4 6
THROTTLE
BODY
(3.8L)
75149
4.(K22) TP SIGNAL 1 CIRCUIT SHORTED TO THE (K855) 5-VOLT SUPPLY CIRCUIT
1. Turn the ignition off.
2. Measure the resistance between the (K22) TP Signal 1
circuit and the (K855) 5-volt Supply in the Throttle Body 3
harness connector. 2
1 0
2 6 BLACK
0
Is the resistance below 100 Ohms?
Yes 1 3
4 6
Repair the short between the (K22) TP Signal 1 circuit
and the (K855) 5-volt Supply circuit.
Perform the PCM VERIFICATION TEST. (Refer to 28 - THROTTLE
DTC-Based Diagnostics/MODULE, Powertrain Control BODY
(PCM) - Standard Procedure). (3.8L)
75151
No
Go To 5
5.(K22) TP SIGNAL 1 CIRCUIT SHORTED TO THE (K124) ETC MOTOR (+) CIRCUIT
1. Measure the resistance between the (K22) TP Signal 1
circuit and the (K124) ETC Motor (+) in the Throttle Body
harness connector.
Is the resistance below 100 Ohms?
Yes
Repair the short between the (K22) TP Signal 1 circuit
and the (K124) ETC Motor (+) circuit.
Perform the PCM VERIFICATION TEST. (Refer to 28 -
DTC-Based Diagnostics/MODULE, Powertrain Control 3
(PCM) - Standard Procedure). 2
0
1
1 6 BLACK
0
No
1 3
Go To 6
4 6
THROTTLE
BODY
(3.8L)
75109
6.(K22) TP SIGNAL 1 CIRCUIT SHORTED TO THE (K126) ETC MOTOR (-) CIRCUIT
1. Measure the resistance between the (K22) TP Signal 1
circuit and the (K126) ETC Motor (-) in the Throttle Body
harness connector.
3
2
1 0
Is the resistance below 100 Ohms? 4 6 BLACK
0
Yes
1 3
Repair the short between the (K22) TP Signal 1 circuit
4 6
and the (K126) ETC Motor (-) circuit.
Perform the PCM VERIFICATION TEST. (Refer to 28 -
DTC-Based Diagnostics/MODULE, Powertrain Control
(PCM) - Standard Procedure). THROTTLE
BODY
(3.8L)
No 75111
Go To 7
7.(K22) TP SIGNAL 1 CIRCUIT OPEN
CAUTION: Do not probe the PCM harness connectors.
Probing the PCM harness connectors will
damage the PCM terminals, resulting in poor
terminal to pin connection. Install the PCM
Pinout Box 8815A to perform diagnosis.
1. Measure the resistance of the (K22) TP Signal 1 circuit
between the Throttle Body harness connector and the
appropriate terminal of PCM Pinout Box 8815A .
3
Is the resistance below 5.0 Ohms? 2
C2-21 1 0
Yes 6 0
1 8 BLACK
Go To 8 9 15
16 23 1 3
No 24 30 4 6
31 38
Repair the open in the (K22) TP Signal 1 circuit. THROTTLE
PCM PINOUT
Perform the PCM VERIFICATION TEST. (Refer to 28 - BODY
BOX 8815 (3.8L)
DTC-Based Diagnostics/MODULE, Powertrain Control
(PCM) - Standard Procedure).
75113
8.(K922) TP SENSOR GROUND CIRCUIT OPEN
1. Measure the resistance of the (K922) TP Sensor Ground
circuit between the Throttle Body harness connector and
the appropriate terminal of PCM Pinout Box 8815A .
3
2
C2-15 1 0
Is the resistance below 5.0 Ohms? 0
3
1 8 BLACK
Yes
9 15
16 23
Go To 9 1 3
24 30 4 6
31 38
No
THROTTLE
PCM PINOUT
BODY
Repair the open in the (K922) TP Sensor Ground circuit. BOX 8815 (3.8L)
Perform the PCM VERIFICATION TEST. (Refer to 28 -
DTC-Based Diagnostics/MODULE, Powertrain Control 75155
(PCM) - Standard Procedure).
9.THROTTLE POSITION SENSOR 1 VOLTAGE
1. Turn the ignition off.
2. Connect the C2 Powertrain Control Module (PCM) harness
connector.
3. Turn the ignition on.
4. With the scan tool, read the Throttle Position Sensor 1
voltage.
NOTE: The sensor voltage should be approximately 5.0
volts (plus or minus .1 of a volt) with the Throttle
Body connector disconnected.
3
5. Turn the ignition off. 2
1 2
6. Connect a jumper wire between the (K22) TP Signal 1 0
BLACK
circuit and the (K922) TP Sensor Ground circuit in the
3
Throttle Body harness connector.
7. Turn the ignition on. 1 3
8. With a scan tool, read the Throttle Position Sensor 1 4 6
voltage.
THROTTLE 6
NOTE: The sensor voltage should be approximately 0.0
BODY
volts (plus or minus .1 of a volt) with the jumper
(3.8L)
wire in place.
75055
Does the scan tool display the voltage as described above?
Yes
Go To 10
No
Go To 11
10.THROTTLE BODY
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Throttle Body and the
Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for the DTC to reset during the wiggle test.
6. Perform any Technical Service Bulletins that may apply.
Were any problems found?
Yes
Repair as necessary.
Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control
(PCM) - Standard Procedure).
No
Replace and Throttle Body in accordance with the Service Information. Disconnect the battery prior to replacing the
Throttle Body. With the scan tool, perform the ETC relearn function after replacement.
Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control
(PCM) - Standard Procedure).
11.POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Throttle Body and the
Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for the DTC to reset during the wiggle test.
6. Perform any Technical Service Bulletins that may apply.
Were any problems found?
Yes
Repair as necessary.
Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control
(PCM) - Standard Procedure).
No
Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information.
Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control
(PCM) - Standard Procedure).
