What Does P2135 Mean?
The PCM has detected that throttle/pedal position sensors A and B are not providing signals that correlate properly with each other. These redundant sensors should track proportionally; a mismatch indicates sensor failure, wiring issue, or throttle body fault.
Safety Warning
Vehicle will likely enter limp mode with severely reduced power and maximum speed limited to 20-30 mph. Safe to drive slowly to repair facility but not highway speeds.
Common Causes
40%
Failed accelerator pedal position (APP) sensor with one sensor element degraded
30%
Failed throttle position sensor (TPS) on electronic throttle body
15%
Damaged wiring or corroded connector affecting one sensor circuit
10%
Low system voltage or failing battery causing sensor voltage instability
5%
Carbon buildup or mechanical binding in throttle body affecting sensor readings
Diagnostic Steps
1
Step 1: Monitor live data for both TPS sensor A and B signals; compare voltage relationship during throttle operation (should track proportionally)
2
Step 2: Check APP sensor signals A and B with scan tool during slow pedal depression (typically one increases 0-5V, other decreases 5-0V)
3
Step 3: Inspect throttle body for excessive carbon buildup; clean if necessary and perform throttle relearn procedure
4
Step 4: Verify reference voltage (5V) and ground circuits at both APP sensor and throttle body with multimeter
5
Step 5: Replace failed sensor (APP or TPS/throttle body) based on which sensor pair shows incorrect correlation
Estimated Repair Cost
$200 - $800
Parts + labor, varies by vehicle and location
The PCM has detected that throttle/pedal position sensors A and B are not providing signals that correlate properly with each other. These redundant sensors should track proportionally; a mismatch indicates sensor failure, wiring issue, or throttle body fault.
The most common cause of P2135 (Throttle/Pedal Position Sensor/Switch A / B Voltage Correlation) is: Failed accelerator pedal position (APP) sensor with one sensor element degraded
Typical repair costs for P2135 range from $200 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle will likely enter limp mode with severely reduced power and maximum speed limited to 20-30 mph. Safe to drive slowly to repair facility but not highway speeds.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2135 to identify the root cause.
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Quick Info
Category
Powertrain
System
Electronic Throttle Control
Difficulty
Type
Generic (SAE)
Recommended Tools
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