Quick answer
Code P0229 is “Throttle/Pedal Position Sensor/Switch ‘C’ Circuit Intermittent.” The ECM has detected an intermittent or erratic signal from the “C” throttle position (TPS) or accelerator pedal position (APP) sensor circuit. “C” is the third TPS/APP element, not a bank. Common causes are a worn sensor with intermittent internal contact, or a chafed/corroded connector or wire in the C circuit.
The P0229 trouble code points to an intermittent or erratic signal from the “C” throttle/pedal position sensor circuit, which the ECM uses to know how far you're pressing the pedal. This guide covers the symptoms, causes and fixes for P0229, and shows where a wiggle-test plus live data on a scan tool like the iCarsoft CR Max P catches the dropout.
1What Does the P0229 Code Mean?
P0229 is a generic powertrain DTC set when the ECM detects an intermittent or erratic signal from the “C” throttle position / accelerator pedal position sensor circuit. The TPS/APP “C” is a potentiometer on a 5V reference; when the ECM logs a set number of erratic readings over a programmed period, it stores P0229. The “C” denotes the third TPS/APP element — it is not an engine bank.
2Symptoms of the P0229 Code
- Check engine light on (often intermittent).
- Hesitation or surging on acceleration.
- Delayed or hard starting, especially on a cold start.
- Black smoke from the exhaust, notably on startup.
- Reduced fuel efficiency.
- Possible intermittent limp mode / reduced power.
- Accompanying throttle or emissions-related codes.
3Common Causes of the P0229 Code
- Faulty, worn or misadjusted TPS/APP sensor (intermittent internal contact).
- Open, shorted, chafed or corroded “C” circuit wiring.
- Loose or corroded sensor connector / poor pin contact.
- Binding, dirty or damaged throttle plate or linkage affecting sensor travel.
- Damaged 5V reference or ground feeding the “C” circuit.
- Bad PCM or a PCM programming error (verify last).
4How Serious Is P0229? Can You Keep Driving?
Treat P0229 with some urgency. The throttle/pedal position signal is central to drivability, so an intermittent “C” circuit can cause sudden hesitation, surging or limp mode. It's drivable, but intermittent throttle faults can produce unexpected power loss — repair it soon.
5How to Diagnose the P0229 Code
The key is to provoke and capture the intermittent:
- Scan codes and freeze-frame with a scan tool such as the iCarsoft CR Max P.
- View live data: graph TPS/APP “C” voltage while sweeping the pedal — watch for dropouts, spikes or dead spots.
- Wiggle-test the connector and harness while monitoring live data to force the intermittent.
- Check the “C” circuit 5V reference, ground and signal continuity; inspect for chafing or corrosion.
- Inspect the throttle body and plate for binding or carbon buildup.
6Steps to Fix the P0229 Error Code
- Confirm the code and freeze-frame; note when it sets (cold start, acceleration).
- Inspect and clean the TPS/APP connector; repair corrosion, loose pins and chafed or shorted “C” wiring.
- Verify the 5V reference and ground at the sensor; repair circuit faults.
- Monitor live “C” voltage through a full pedal sweep with a wiggle-test to catch the dropout.
- Inspect and clean the throttle body/plate; fix any binding or linkage issue.
- If the signal is erratic with good wiring and reference, replace the TPS/APP sensor and perform any required throttle/pedal relearn.
- Clear the code, road-test (including a cold start), and re-scan to confirm a stable “C” signal.
7Why the Throttle Signal Matters
In a drive-by-wire car there's no cable — the pedal sensor is the only thing telling the ECM how much throttle you want, and the ECM uses redundant elements (A, B, C) to cross-check that request. When the “C” signal flickers, the ECM can't trust the pedal, so it pulls power back into a safe mode. A solid, intermittent-free signal is what keeps the throttle responsive and predictable.
8Which iCarsoft Tool to Use
The iCarsoft CR Max P is well suited to a P0229. Its live data graphs the TPS/APP “C” signal while you sweep the pedal and wiggle the harness, so you can actually catch the intermittent dropout — and on supported vehicles it runs the throttle relearn after a sensor change.
With CAN-FD support and coverage for 58 vehicle makes, it also confirms a stable signal after the repair.
Recommended for P0229
iCarsoft CR Max P
Pro bi-directional scan tool with live throttle/pedal data, throttle relearn, CAN-FD and full-system diagnostics across 58 car brands — to catch the intermittent and verify a P0229 repair.
$599.99 · was $819.99 · lifelong free updates
Shop CR Max P See full specs9P0229 Repair Cost
Cost depends on whether it's the wiring, the sensor or an integrated throttle body. Typical ranges (parts + labor):
| Repair | Typical cost |
|---|---|
| Diagnostic (scan) | $75–$150 |
| TPS / APP sensor replacement | $150–$400 |
| Throttle body replacement (if integrated) | $300–$700 |
| Wiring / connector repair | $75–$250 |
| Throttle / pedal relearn | $50–$120 |
These are general estimates — get a quote once the specific cause is confirmed.
10Prevention & Regular Maintenance
- Keep the throttle body clean to prevent binding that stresses the sensor.
- Inspect and protect the TPS/APP harness from chafing and heat.
- Keep sensor connectors clean, tight and corrosion-free.
- Avoid cheap aftermarket wiring taps near the throttle circuit.
- Address minor throttle hesitation early before the circuit degrades to intermittent failures.
11Related Trouble Codes
12P0229 — Frequently Asked Questions
What does the “C” mean in P0229?
It refers to the third throttle/pedal position sensor element — not an engine bank.
Is it safe to drive?
Use caution — intermittent throttle faults can cause sudden hesitation or limp mode, so repair it promptly.
Why is the code so hard to find?
It's intermittent — use live data plus a wiggle-test on the connector and harness to provoke and capture the fault.
Do I need a relearn after replacing the sensor?
Many electronic-throttle systems require a throttle / pedal relearn with a capable scan tool after replacement.
How do I reset the P0229 code?
Repair the wiring or sensor first, then clear the code with a scan tool such as the iCarsoft CR Max P and verify a stable signal.
13References
- SAE International, J2012 — Diagnostic Trouble Code Definitions (the standard that defines P0229).
- Wikipedia, Throttle position sensor — background on TPS and drive-by-wire throttle control.
