DTC P0122 Throttle Position (TP) Sensor Circuit Low Voltage. Oldsmobile Aurora 1999

For 1990-2009 cars only

Makes 🢒 Oldsmobile 🢒 1999 🢒 Aurora 🢒 Engine 🢒 Engine Controls - 4.0L and 4.6L 🢒 DTC P0122 Throttle Position (TP) Sensor Circuit Low Voltage

Cell 21: IAT, ECT, TP, MAP Sensors
Engine Controls Components
OBD II Symbol Description Notice
ESD Notice

Circuit Description

The Throttle Position sensor is potentiometer. A 5 volt reference is provided on CKT 1688 and ground is provided on CKT 552. The TP sensor signal CKT 417 varies between ground and 5 volts based on the position of the throttle plates. At low throttle angle, the TP sensor signal voltage is low. The PCM uses TP sensor information to determine idle, Wide Open Throttle (WOT), deceleration enleanment and acceleration enrichment. DTC P0122 sets when the PCM detects a TP sensor signal that is too low. The PCM tests the TP sensor feedback every 100 ms. If the TP sensor reading is 0.1 volts or less, such as when the signal is open or shorted to ground, the PCM sets DTC P0122.

Conditions for Running the DTC

Engine speed 600 RPM or greater.

Conditions for Setting the DTC

The TP sensor reading is 0.1 volts or less.

Action Taken When the DTC Sets

•	PCM disables the torque converter clutch.

•	PCM calculates a TP sensor value based on MAP and engine speed inputs.

•	PCM disables fourth gear.

•	The PCM will illuminate the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.

•	The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records.

Conditions for Clearing the MIL/DTC

•	The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.

•	A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.

•	A History DTC will clear after forty consecutive warm-up cycles with no failures of any emission related diagnostic test.

•	Use a scan tool to clear DTCs.

•	Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in Powertrain Control Module Description .

Diagnostic Aids

If fault is not present perform Powertrain Ground Check and also review Failure Rec. to determine conditions under which and how long ago the DTC set.

Test Description

The numbers below refer to the step numbers on the Diagnostic Table.

If the TP sensor or circuitry are open, the TP sensor parameter will read 0.1 volts or less.

If fault is not present monitor the scan tool display for this sensor while manipulating the vehicle's electrical harness. A change in sensor output while manipulating the harness may indicate a circuit fault.

Checking if circuitry from sensor to PCM is able to respond to a 5 volt signal on the TP input. A reading of 4.5 volts or more means the wiring and the PCM are OK.

Disconnect the suspect sensor and re-measure the resistance between the 5 volt reference and sensor ground circuits. If infinite resistance is measured the sensor is shorted.

Step

Action

Value(s)

Yes

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Turn the key ON.
Using a scan tool view the TP display.

Is the value displayed the same or less than the value specified?

0.1 volts

Go to Step 3

Fault not present. Refer to Test Descriptions

Turn the key to OFF.
Disconnect the TP sensor.
Using a fused jumper connect the sensor signal and 5 volt reference circuits together.
Turn the key ON.

Is the TP value displayed on the scan tool higher than the value specified?

4.5 volts

Go to Step 13

Go to Step 4

Remove the jumper.
Using DMM J 39200 measure the voltage to ground at the 5 volt reference circuit terminal.

Is the voltage the same or higher than the voltage specified?

4.5 volts

Go to Step 5

Go to Step 7

Record the fluid life indexes, turn the key to OFF and wait 30 seconds.
Disconnect PCM connector C1.
Measure and record the resistance between the sensor signal and the sensor ground circuit.
Measure and record the resistance between the sensor signal circuit and a known good engine ground.

Is the resistance of both checks the same or more than the value specified?

10K ohms

Go to Step 6

Go to Step 9

Measure the resistance of the sensor signal circuit between the PCM connector terminal and the TP sensor connector terminal.

Is the resistance more than the value specified?

5 ohms

Go to Step 10

Go to Step 19

Record the fluid life indexes, turn the key to OFF and wait 30 seconds.
Disconnect PCM connector C1.
Measure and record the resistance between the 5 volt reference circuit and the sensor ground circuit.
Measure and record the resistance between the 5 volt reference circuit and a known good engine ground.

Is the resistance of both checks the same or more than the value specified?

10K ohms

Go to Step 8

Go to Step 12

Measure the resistance of the 5 volt reference circuit between the TP sensor connector terminal and the PCM connector terminal.

Is the resistance less than the value specified?

5 ohms

Go to Step 15

Go to Step 11

Repair the short to ground in the TP Sensor Signal circuit or the short between the TP Sensor Signal and the TP Sensor ground circuit.

Is the repair complete?

Go to Powertrain Control Module Diagnosis for Verify Repair

Repair the open in the TP Sensor Signal circuit.

Is the repair complete?

Go to Powertrain Control Module Diagnosis for Verify Repair

Repair the open in the TP sensor 5 Volt Reference circuit.

Is the repair complete?

Go to Powertrain Control Module Diagnosis for Verify Repair

Repair the short to ground in the TP Sensor 5 volt reference circuit or the short between the TP Sensor 5 volt reference circuit and the TP Sensor ground circuit.

Is the repair complete?

Go to Powertrain Control Module Diagnosis for Verify Repair

Check terminal contact at the TP sensor.
Repair terminal contact if needed.

Was terminal contact repaired?

Go to Powertrain Control Module Diagnosis for Verify Repair

Go to Step 14

Replace the TP sensor. Refer to TP Sensor Replacement.

Is the replacement complete?

Go to Powertrain Control Module Diagnosis for Verify Repair

A short may exist on another 5 volt reference circuit.

•	Reconnect all sensors.

•	Disconnect PCM connector C1.

•	Using DMM J 39200 measure and record the resistance between the 5 volt reference circuit and the sensor ground circuit for each of the following sensors:

-	the MAP sensor

-	the EGR valve pintle position sensor

-	the Fuel Tank Pressure sensor

Is the resistance of any check less than the value specified?

10K ohms

Go to Step 17

Go to Step 16

Measure and record the resistance between the 5 volt reference circuit and a known good engine ground for each of the following sensors:

•	the MAP sensor

•	the EGR valve pintle position sensor

•	the Fuel Tank Pressure sensor

Is the resistance of any check less than the value specified?

10K ohms

Go to Step 18

Go to Step 19

Repair the 5 volt reference circuit to sensor ground short or replace the shorted sensor for the circuit that measured low in Step 15. Refer to Test Descriptions.

Is the repair or replacement complete?

Go to Powertrain Control Module Diagnosis for Verify Repair

Repair the 5 volt reference circuit short to engine / body ground for the sensor that measured low in Step 16.

Is the repair complete?

Go to Powertrain Control Module Diagnosis for Verify Repair

Check terminal contact at PCM Connector C1.
Repair terminal contact if needed.

Was terminal contact repaired?

Go to Powertrain Control Module Diagnosis for Verify Repair

Go to Step 20

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .

Is the replacement complete?

Go to Powertrain Control Module Diagnosis for Verify Repair