P0122
High SeverityThrottle Position Sensor A Circuit Low
Fuel System
P0122 — Instant Answer
Throttle Position Sensor A Circuit Low
Severity: HIGH SEVERITY
Meaning: TPS voltage is below minimum threshold. The ECM cannot determine throttle position accurately.
Safe to drive? NO if CEL is flashing. YES with caution if solid, but repair this week.
Estimated repair cost: $20 - $100
Most common causes:
- 1. Faulty TPS (35-45% of cases)
- 2. Wiring short to ground (10-25% of cases)
- 3. Bad TPS connector (10-25% of cases)
- 4. ECM driver fault (5-10% of cases)
Symptoms
- ⚠️Engine stuck at idle
- ⚠️No acceleration response
- ⚠️Limp mode
- ⚠️Check engine light
Related Symptoms
Common Causes
How to Diagnose P0122
- 1Check TPS connector and wiring
- 2Measure TPS signal voltage
- 3Check 5V reference wire
- 4Replace TPS
OEM Diagnostic Flowchart
Scroll to load technician if/then branches.
Read live data and freeze frame for P0122 to pinpoint the cause before buying parts.
TopScan
$51.27
DIYers who want phone-based scanning
View on TOPDON
ArtiLink600
$99
DIYers working on ABS/airbag systems
View on TOPDONGot a repair estimate for P0122? Check if the quote is fair before ordering parts.
Turn This Into a Confident Next Step
Verify the likely fault first, then compare a quote before you approve expensive work.
Affiliate disclosure: We may earn a commission at no extra cost to you.
View supporting tool options
OBD2 scanner
Read codes and freeze-frame data before you guess at the fault.
Most diagnostic jobs start with a scan tool and a verified code path.
Shop on Amazon →Battery tester
Check cranking and charging health before replacing expensive parts.
A weak battery can mimic alternator or starter problems.
Shop on Amazon →Multimeter kit
Confirm voltage, continuity, and sensor power with one simple kit.
A meter is the cheapest way to rule out a bad circuit fast.
Shop on Amazon →Related Resources
Repair guides, symptom pages, and wiring diagrams related to P0122.
Related Codes
General fault in the TPS circuit. The TPS tells the ECM how far the throttle is open.
The TPS reading does not match expected values based on MAP, RPM, and other inputs. Erratic readings indicate a worn TPS.
TPS voltage is above maximum expected. ECM sees the throttle as more open than it actually is.
Frequently Asked Questions
- Why wont my car accelerate with P0122?
- The ECM thinks the throttle is fully closed, so it limits engine power. A new TPS usually fixes this immediately.
- Can I drive in limp mode?
- You can drive slowly to get home or to a shop, but speed is limited. Do not drive far in limp mode.
Get the Complete Maintenance Schedule for P0122 drivers
Oil, filters, belts, brakes, and fluid intervals sent to your inbox. Unsubscribe anytime.
Not sure you want to DIY? Compare local shop pricing first.
Author & Review
Written by AllOEMManuals Editorial Team. Reviewed by ASE-certified technicians and updated with factory-reference checks for fitment-sensitive steps.
This guide was drafted with AI assistance and reviewed for accuracy by a human editor.
Last updated: 2026-05-07