P2135 – Accelerator pedal position (APP) / Throttle position (TP) sensor/switch A/B – voltage correlation
| Code | Fault Location | Probable Cause |
|---|---|---|
| P2135 | Accelerator pedal position (APP) / Throttle position (TP) sensor/switch A/B - voltage correlation (Buy Part On Amazon) | Wiring, APP / TP sensor/switch / Wiring, TP sensor/switch |
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Table of Contents
- What Does Code P2135 Mean?
- What are the common causes of code P2135?
- What are the symptoms of code P2135?
- How do you troubleshoot code P2135?
- Codes Related to P2135
- Get Help with P2135
What Does Code P2135 Mean?
Largely, vehicle manufacturers have switched from cable-operated throttle bodies to electronically-controlled throttle body designs. Known as drive-by-wire, these systems use a sensor at the accelerator pedal to determine its position. Then, a signal is sent to a sensor on the throttle body to adjust the position of the throttle plate. This action is performed in real-time, and response is virtually instantaneous. The throttle body has two throttle position sensors (TPS) sensors that provide a voltage signal to the powertrain control module, along with a 5V reference circuit an a common low-reference circuit. The two TPS sensors operate inversely -- one has an increasing voltage when throttle is applied and one has decreasing voltage on throttle application. If the two TPS sensor readings don't correlate in the PCM for more than a couple seconds, DTC P2135 is set in the PCM.What are the common causes of code P2135?
- TPS failure (most common concern)
- Poor connection or bent pins in TPS connector
- Chafed or corroded wiring
- APP sensor failure
- PCM internal short (least likely but possible)
What are the symptoms of code P2135?
- Hard starting
- Little to no throttle response
- Check Engine light illuminated
- Sudden loss of engine power while driving
- Possible stalling condition when slowing to a stop
How do you troubleshoot code P2135?
Before attempting to diagnose and repair the concern, determine if your vehicle is involved in a service bulletin from the manufacturer. Many General Motors vehicles have a TSB extending the coverage on throttle body side cover replacement to repair a condition such as this. It's also a known issue on many Nissan vehicles. The TPS system is made up of three main components that communicate for accurate throttle response: the accelerator position (APP) sensor, the TPS sensor, and the powertrain control module (PCM). Diagnosing DTC P2135 can be achieved with just a digital volt-ohmeter to measure resistance, and vehicle-specific wiring diagrams that you can obtain from major parts retailers or the dealer. DTC P2135 is set when there is high resistance on any of the four wires to the TPS sensor. With the ignition off, test for resistance between the low-voltage reference circuit and ground. If resistance is higher than 5 ohms, check the circuit for corrosion or chafed, cracked, or loose wires or connectors. With the ignition on, test for 5V reference voltage. The value should be between 4.8 and 5.2V. Higher voltage indicates a short to voltage while low reference voltage indicates a short to ground or open in the circuit. Trace for those issues. Test voltage at the TPS connector for each signal circuit, one at a time. One signal circuit should remain below 1V without throttle input. Slowly apply throttle, monitoring the voltage for a smooth increase. Wide open throttle (WOT) should near 5V. The second signal circuit should maintain at or near 5V with no throttle application. On smooth pedal application, the voltage should drop until WOT results in near 0V. If either of the signal circuits spike when the accelerator is pressed, the TPS needs to be replaced. Many TPS are serviced as part of the throttle body assembly.
If neither of the signal circuits respond, the APP sensor is likely at fault. Test for resistance at the APP sensor connector. The APP sensor is usually part of the accelerator pedal assembly. With the key off, check for resistance changes as the pedal is pressed. If none is found, replace the APP sensor. 
If the TPS wiring tests ok and the APP sensor operates as designed, the PCM is likely the culprit. Replace with a known good PCM. In many vehicles, the PCM will require programming to your specific vehicle and options.Codes Related to P2135
- P0120 – Throttle position (TP) sensor A/accelerator pedal position (APP) sensor / switch A -circuit malfunction
- P0122 – Throttle position (TP) sensor A/accelerator pedal position (APP) sensor / switch A -low input
- P0123 – Throttle position (TP) sensor A/accelerator pedal position (APP) sensor / switch A -high input
- P0220 – Throttle position (TP) sensor B/accelerator pedal position (APP) sensor / switch B -circuit malfunction
- P0222 – Throttle position (TP) sensor B/accelerator pedal position (APP) sensor / switch B -low input
- P0223 – Throttle position (TP) sensor B/accelerator pedal position (APP) sensor / switch B -high input
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