2011 GMC Sierra 1500 P2135 Code: Pedal Position Sensor A/B Correlation Issue After Multiple Repairs
Hi everyone, I'm looking for help with a persistent issue on my 2011 GMC Sierra 1500 (5.3L Flex Fuel). The problem started with a 'Service Traction Control' message, followed by 'Traction Control Off' and reduced engine power. After scanning the vehicle, I found a throttle position sensor (TPS) fault. The dealer replaced the TPS and performed a relearn procedure — it worked for a couple of days. The issue returned with a permanent P2135 code: Pedal Position Sensor A/B Correlation. I installed a complete new throttle pedal assembly with its sensor, but the code persists. I've also cleaned the main ground connection, swapped out the battery (thinking weak voltage might be causing electronic issues), and replaced the alternator due to inconsistent voltage readings — the voltmeter would spike to 15V then drop to around 10V. Despite these efforts, the vehicle still enters reduced engine power mode. All wiring appears secure, no visible breaks, and I believe the pigtail was previously replaced. I'm mechanically inclined but have run out of troubleshooting steps. What else should I try before taking it to a dealer? Is there any known diagnostic procedure or common cause for this specific P2135 code on 2011 GMC Sierra models? Any insights would be greatly appreciated!
Check with your dealer about the extended coverage policy — specifically, does it cover the P2130 code under RPO (Regular Production Option)? Look up '11273B — Special Coverage Adjustment – Throttle Position Sensor Replacement'. There may be a public copy available online that outlines what's covered under this policy.