What this code means
P2135 often means the PCM may see a mismatch between the throttle position sensor signals.
What the vehicle may do
- The vehicle may limit throttle response.
- A warning light may come on.
- The vehicle can feel like it does not respond normally to accelerator input.
Possible fault areas
- Possible throttle position sensor circuit issue.
- Possible throttle body internal circuit issue.
- Possible wiring or connector issue.
- Possible PCM fault after other checks prove normal.
Diagnostic path
Opening context
On this Accord Hybrid, P2135 is a throttle position plausibility fault. In plain language, the PCM may be seeing the two throttle position signals disagree with each other. The vehicle may limit throttle response, set a warning light, or feel like it will not respond normally to pedal input. The broad fault areas can include the throttle position sensor circuits, the throttle body internal circuit, connector or wiring issues, and, after the other checks prove normal, a possible PCM fault. Start with the basic system checks, and if other codes are present, check what they mean first so you are not chasing the wrong symptom.
Start the scan-tool test
Begin by turning the vehicle to the ON mode. Then run the HDS ETCS TAC test. This is the broad test in this path, and it can be done before the individual inspections because it includes the inspection items that follow. If that test does not pass, keep going through the individual checks to find which part of the path failed.
Check THL1 and THL2 for a shorted wire-to-wire condition
For the THL1 and THL2 shorted-wire inspection, do not just unplug the PCM right away. Before disconnecting the PCM connector, use the HDS to jump the SCS line, then wait more than 1 minute. After that, set up the test with PCM connector B, the 101 pin connector, disconnected, and the 6 pin throttle body connector disconnected. Perform the THL1 and THL2 wire-to-wire inspection as laid out in the test table. The normal result is more than 1 MΩ. If that inspection is abnormal, the problem is in the circuit.
Inspect the TP sensor circuit path
Next, move to the TP sensor circuit inspection. Again, before disconnecting the PCM connector, jump the SCS line with the HDS and wait more than 1 minute. This inspection assumes the external circuit is normal before you move into the next check. With that precondition met, prepare the test with PCM connector B, the 101 pin connector, disconnected.
Check the throttle body internal circuit
Now perform the throttle body internal circuit inspection using the test table. The normal result is no continuity. If that inspection is abnormal, the problem is with the throttle body.
PCM decision point and takeaway
If the other inspection items show a normal condition, the remaining decision in this path is that there is a problem with the PCM. The takeaway is to keep the diagnosis in order: run the scan-tool test, isolate the THL1 and THL2 circuit, confirm the TP sensor circuit path, check the throttle body internal circuit, and only then make the PCM call if the other inspections are normal. For more diagnostic training, visit stepdiagnostics.com.
Final check
Follow the diagnostic path in order and prove each part of the throttle position signal path before making the final fault call.
For more guided automotive diagnostics, visit STEP Diagnostics.
