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2009 Chevy Malibu P2135 Code: Throttle Position Sensor Issue & Fix Guide

Model: 2009 Chevy Malibu Fault Code: P2135 Posted:

Hi everyone, I recently joined this forum and want to thank all members for the helpful discussions — your insights are invaluable. I'm currently troubleshooting a persistent issue with my 2009 Chevy Malibu LS 2.4L, where the vehicle exhibits engine shaking, reduced power, and activation of the check engine light along with stability and traction control warnings. The diagnostic trouble code (DTC) displayed is P2135: 'Throttle / Pedal Position Sensor / Switch A/B Voltage Correlation'. I've already cleaned the throttle body, which I read is a common fix online, but the problem persists. After reviewing various threads, I'm now wondering whether this issue stems from a faulty sensor or wiring problems — especially since many users have replaced multiple components without success. Below are my current diagnostic readings: - DTCFRZF: P2135 - FUELSYS1: CL - FUELSYS2: N/A (2.4L engine has only one fuel system) - LOAD_PCT(%): 29.4 - ECT(°F): 144 - SHRTFT1(%): -3.1 - LONGFT1(%): -0.8 - MAP(inHg): 10.0 - RPM(/min): 990 - VSS(mph): 0 - SPARKADV(°): 5 - IAT(°F): 52 - MAF(lb/min): 0.663 - TP(%): 20.8 - RUNTM(sec): 33 - EVAP_PCT(%): 0.0 - FLI(%): 40.4 - WARM_UPS: 0 - CLR_DIST(mile): 0 - EVAP_VP(inH2O): 0.440 - BARO(inHg): 30.1 - CATEMP11(°F): 924.80 - VPWR(V): 14.965 - LOAD_ABS(%): 24.0 - EQ_RAT: 0.999 - TP_R(%): 6.3 - AAT(°F): 32 - TP_B(%): 25.9 - APP_D(%): 17.6 - APP_E(%): 8.6 - TAC_PCT(%): 9.4 I'm seeking expert advice — if you're a mechanic or have experienced this issue before, please share your insights. I'd greatly appreciate any suggestions on diagnosis, part replacement, or troubleshooting steps. Thank you in advance for your time and knowledge!

Related fault codes
P2135
Comments (13)
Anonymous 2017-12-15 12:35

The Throttle Position (TP) and TP_B signals should match closely. If they don't, the P2135 code will trigger. Use a scan tool to monitor these two parameters in real time to confirm if the issue is sensor-related. A dedicated throttle position sensor replacement kit is available — check South Main Auto Repair.com for detailed video guides.

Anonymous 2017-12-16 09:44

There's a Technical Service Bulletin (TSB) relevant to 2008–2012 Malibu models that addresses this issue. While it may require PCM reflash, common root causes include faulty throttle position sensors or wiring between the throttle body and powertrain control module (PCM). If you have a multimeter, perform voltage checks on the sensor circuits. Most cases resolve with replacing the throttle body and completing an idle relearn procedure. AutoZone offers Bosch (around $165) or AC Delco ($200) sensors — I recommend verifying circuit integrity and using live data from a scan tool. A Snap-on scanner is highly recommended for accurate diagnostics. Let me know if you'd like further guidance.

Anonymous 2017-12-16 10:13

I made a mistake earlier — upon checking, there's an official GM TSB (No. 14582A) specifically for 2008–2012 Malibu models with P2135. Dealerships cover repairs under warranty for up to 10 years or 120,000 miles. I can share the full document or help you search it via Google. Please contact your local dealer to confirm eligibility and details.

Anonymous 2017-12-16 15:28

Cj1 — I watched the video and found it very helpful. I'll try replacing the TPS sensor next. Autojoe — I'm at 122,000 miles now, so dealer coverage might not apply. I’ll likely need to troubleshoot independently and explore possible root causes beyond just a sensor.

Anonymous 2017-12-16 19:54

I can provide GM-specific testing procedures and TPS replacement instructions if you'd like — just send me an email for direct support.

Anonymous 2017-12-16 20:23

Autojoe — I'm attempting to fix this myself without taking the car to a mechanic. Any advice or tips would be greatly appreciated!

Anonymous 2017-12-17 13:13

I recommend purchasing a full throttle body rebuild kit and replacing the TPS assembly as part of the repair.

Anonymous 2017-12-17 13:42

I'm considering buying a used throttle body from a junkyard. Would you say that's better than buying a new replacement kit? Also, without a live scan tool, I can't verify if signals agree after installation. Will the car perform an idle relearn on its own, or do I need to visit a shop for programming?

Anonymous 2017-12-17 19:14

A used throttle body from a junkyard is possible — but be cautious: outdoor storage can cause moisture damage and poor electrical connections. If cost is low and the seller offers a guarantee or refund, it's worth considering. However, you cannot verify functionality post-installation. For idle relearn, you can perform a manual process without a scan tool: start in park, idle for 3 minutes, turn off for 1 minute, restart and idle again for 3 minutes, then drive normally. The PCM will learn the new settings over time.

Anonymous 2017-12-17 20:08

Joe — I’ll probably go with a replacement kit since it’s only around $30. My main concern is that I won’t have access to live data to confirm whether TP and TP_B signals agree after installation. If the sensor isn't faulty, I may need to replace the throttle body or acceleration sensor instead. Does anyone know of an affordable (under $100) OBD2 scanner that supports real-time 'agree/disagree' monitoring? My current OBD2 tool only shows freeze frame data and readiness values — no live readings. Any recommendations for a reliable, budget-friendly tool?

Anonymous 2017-12-18 18:56

P2135 specifically relates to the dual throttle position sensors inside the throttle body, not the pedal or app sensors. After replacing the TPS and performing a manual idle relearn, the check engine light should clear. Over several ignition cycles, the PCM will erase the code from memory.

Anonymous 2017-12-18 18:57

The same applies to a used throttle body replacement — it may resolve the issue, but without verification of signal agreement or proper installation, results are uncertain.

Anonymous 2023-02-10 18:48

This happened to me on my 2010 Malibu LT 2.4L. The P2135 code appeared once during winter when cold temperatures started — the next occurrence was about a week later. Since then, it triggered more frequently (roughly every hour of driving). Symptoms: - After idling over 5 minutes, the car would enter low-power mode. - In low power mode, engine RPMs would fluctuate between 500–1500 rpm and cause noticeable shaking. Fix: I cleaned the throttle body. Before that, I tried various fixes — checking coolant levels, inspecting connections, replacing the air filter — but nothing worked until cleaning. After deep cleaning of the throttle body crevices (especially around the valve door), the issue resolved for over three weeks. It returned once during a cold start, but has been stable since. I recommend watching this video on how to remove and clean the throttle body: https://www.youtube.com/watch?v=uPvKpbx...channel=TRQ Tip: Focus on cleaning deep crevices where carbon buildup commonly accumulates.