Answer
Apr 18, 2025 - 02:55 AM
To troubleshoot the accelerator position sensor (APP) on your 2013 Honda Civic, you’ll want to start by understanding that it’s part of the drive-by-wire system (so no throttle cable here). The APP sensor is built into the accelerator pedal assembly and sends signals to the PCM to control throttle opening electronically.
Here’s what to check:
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First, scan for DTCs with a scan tool. If you're getting codes like P2122, P2123, P2138, etc., those usually point to APP circuit issues like low voltage, inconsistent signals, or correlation faults between the two sensor tracks.
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Next, with a multimeter, you can back-probe the APP connector and check voltage:
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Turn the ignition ON (engine off).
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You should see one sensor gradually rise from ~0.5V to ~4.5V as you press the pedal, and the second one will usually do the same in the opposite direction (for redundancy).
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If one doesn’t change smoothly or jumps around, that sensor track is likely bad.
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Also check for loose or corroded connectors at the pedal, and make sure the harness isn’t pinched or damaged near the firewall.
If both voltage tracks are good, and no wiring issues are found, but you're still getting codes, it might be time to replace the pedal assembly. It may sound complicated and all, but the OEM manual gives you pinout diagrams, test procedures, and exact voltage ranges for each sensor wire, so it’s really helpful if you’re digging deeper.
In short, if you're seeking how to troubleshoot the APP on your 2013 Civic, you can find the manufacturer's method in this manual. Good luck!
