OBD-II Code · Sensors
P0122
TPS Circuit Low Input
Severity
medium
Worth booking. It costs fuel, emissions or comfort until it is fixed.
Can you drive it
Only if running normally
A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety.
Indicative cost (USD)
$80–$300
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
TPS voltage too low.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
- Poor throttle response
- Limp mode
Likely causes
- Failed TPSMost common
- Wiring short to ground
- Connector issue
Read the full diagnostic procedureP0122 means the Throttle Position Sensor signal voltage is below the floor, typically under 0.2V on a 3-wire potentiometer or under the TPS1 minimum…
P0122 means the Throttle Position Sensor signal voltage is below the floor, typically under 0.2V on a 3-wire potentiometer or under the TPS1 minimum (around 0.3V) on a 6-wire ETC. The ECM reads that as a closed-throttle signal that physically cannot be lower than the calibrated rest position, which means either the sensor has failed shorted to ground, the signal wire is grounded in the harness, or the 5V reference has dropped out and pulled the signal with it. On most platforms the engine drops to a hard limp-home idle (1000-1200 RPM, no pedal response or severely reduced authority) when P0122 sets, because the ECM cannot trust the throttle reading.
Cheapest-first ladder
- key-on engine-off, unplug the TPS connector and backprobe the signal pin at the harness side; with the connector unplugged the signal pin should float to 5V (open-circuit reference).
- If it stays at 0V with the sensor unplugged, the signal wire is shorted to ground between the connector and the ECM. If it goes to 5V unplugged but drops to 0V plugged in, the sensor is internally shorted.
- Verify the 5V reference at the connector reads 4.9-5.1V and ground integrity is under 0.1V drop.
- Don't replace the throttle body before checking the connector for moisture intrusion, because a wet connector will short signal to ground and mimic a dead sensor exactly.
Vehicle-specific patterns2002-2007 Jeep Liberty 3.7L sees P0122 frequently from a chafed TPS signal wire where the harness routes past the intake manifold bracket, shorting t…
- 2002-2007Jeep Liberty 3.7L sees P0122 frequently from a chafed TPS signal wire where the harness routes past the intake manifold bracket, shorting the signal to ground intermittently before going hard-fault.
- 2003-2008Honda Pilot/Odyssey J35 V6 with cable-actuated throttle sees P0122 from internal TPS wiper failure where the element shorts to the case ground at the closed-throttle position.
- 2007-2014GM 5.3L/6.0L Silverado, Tahoe sees P0122 from the throttle body internal TPS1 element failing shorted; the entire throttle body is the GM replacement and it requires a relearn.
- 2005-2010Dodge Charger/Magnum 5.7L Hemi sees P0122 from a known-defective lot of ETC throttle bodies, Mopar TSB acknowledged failures.
Estimated repair$80 to $450.
Look up another code
P0122 — frequently asked
What does a P0122 code mean?
TPS voltage too low.
What causes a P0122 code?
Common causes: Failed TPS; Wiring short to ground; Connector issue.
What are the symptoms of a P0122 code?
Typical symptoms: Check engine light; Poor throttle response; Limp mode.
Is it safe to drive with a P0122 code?
Only if running normally. A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety. Estimated repair: $80-$300.
How do I diagnose a P0122 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
More free tools