🚨 Diagnostic Profile
Vehicle Make: Acura
Trouble Code Description: Accelerator Position Sensor 2 Circuit Malfunction
This code indicates that the Powertrain Control Module (PCM) has detected an abnormal voltage signal from the second Accelerator Pedal Position (APP) sensor. Acura throttle-by-wire systems use multiple sensors within the pedal assembly to cross-reference input signals for safety. When Sensor 2 reports a voltage that is inconsistent with Sensor 1 or falls outside the expected operating range (too high or too low), the PCM triggers this malfunction code and may activate limp-home mode to protect the engine and transmission from erratic throttle response.
🚨 Repair Difficulty Tier
Difficulty Rating: Intermediate
This repair requires a digital multimeter and a capable OBD-II scan tool with live data streaming capabilities to properly diagnose. While the physical replacement of the accelerator pedal assembly is mechanically straightforward, accurately diagnosing whether the fault lies in the wiring harness, the PCM, or the sensor itself requires intermediate electrical diagnostic skill. Improper diagnosis can lead to unnecessary parts replacement.
🛠️ Resolution Steps
Step 1: Preliminary Inspection
- Visually inspect the wiring harness connector at the base of the accelerator pedal assembly for corrosion, bent pins, or loose connections.
- Check for any chafed or pinched wiring along the harness routing near the firewall and under the dash.
- Inspect the pedal assembly for physical damage, excessive play, or debris interference that could affect sensor movement.
- Verify the vehicle battery voltage and grounds are within normal specifications, as low voltage can trigger false sensor codes.
Step 2: Diagnostic Verification
- Connect an OBD-II scan tool capable of live data streaming and monitor APP Sensor 1 and Sensor 2 voltage outputs simultaneously.
- With the ignition on (engine off), slowly depress the accelerator pedal from 0% to 100% and observe that both sensor voltages increase in a smooth, linear, and proportional relationship to one another.
- Use a digital multimeter to backprobe the sensor connector and verify reference voltage (typically 5V), signal voltage, and ground continuity match Acura factory specifications.
- Compare live data against Acura’s specified voltage charts to identify if Sensor 2 output is erratic, flatlined, or out of range compared to Sensor 1.
Step 3: Resolution & Reset Process
- If wiring or connector issues are found, repair or replace the damaged harness section and re-verify sensor readings.
- If the sensor voltages remain incorrect after wiring repair, replace the entire accelerator pedal assembly, as APP sensors are not sold individually and are integrated into the pedal unit.
- After replacement, clear the diagnostic trouble codes using the scan tool.
- Perform a throttle body relearn/reset procedure as specified by Acura (this may involve turning the ignition on/off in a specific sequence without starting the engine to allow the PCM to relearn idle and pedal position parameters).
- Road test the vehicle to confirm smooth throttle response and verify the code does not return.
📦 Parts, Labor, and Budget Estimates
Required Components/Software: OEM Acura Accelerator Pedal Position Sensor Assembly, OBD-II diagnostic scan tool with live data capability, digital multimeter, dielectric grease for connector reassembly.
Average Component Price: $120 – $280 for the OEM accelerator pedal assembly, depending on model year and trim.
Estimated Labor Hours: 0.5 to 1.0 hour for diagnosis, and 0.5 hour for pedal assembly replacement. Total shop time typically billed between 1.0 and 1.5 hours.