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2006 Jeep WK Grand Cherokee Overland: P2072, P2100, C121C Codes & Intermittent ESP/TCS Failure

Model: Jeep WK Grand Cherokee Fault Code: P2072 Posted: 2019-03-11 11:48

My 2006 Jeep WK Grand Cherokee Overland with a 5.7L engine and Quadra-Drive II system is experiencing intermittent issues: 1. The ESP/TCS warning light flashes, accompanied by a red ETC (Electronic Throttle Control) indicator. 2. The vehicle occasionally enters limp mode with no throttle response until restarted; it may take several attempts to clear the warnings, which can last from seconds to hours before recurring. 3. Diagnostic trouble codes are showing: C121C (Torque request signal denied), P2072 (Throttle actuator control system ice blockage), and P2100 (Throttle actuator control motor circuit open). 4. I occasionally hear a harsh noise, which feels like the differential is locked during turns—note that my driver's side front half shaft has a torn or melted boot. I previously disconnected the battery to charge it; after reconnection, the vehicle showed only 67% charge, which seemed unusual. The codes cleared and the vehicle ran normally for one full day. On the following day, I removed the Powertrain Control Module (PCM) and inspected it—no visible burns or burning odor were present. The protective gel appeared intact except in the center areas of two chips, possibly where rubber bumpers made contact. After driving again, I could not reproduce the failure, though I did hear the noise. When retrieving codes, only 'Low battery within 50 starts' and C121C were present. I am seeking factual, technical guidance—no speculative advice. I’ve already tested many hypotheses and need reliable, data-backed insights. Any clear explanations or diagnostic steps would be greatly appreciated.

Related fault codes
P2072P2100
Comments (2)
Anonymous 2019-03-11 13:29

No specific component is identified as the root cause. Follow the official troubleshooting procedures outlined in the trouble code documentation. Verify system voltage—intermittent voltage drops in the throttle actuator circuit could be a contributing factor. BBBind.com provides detailed wiring diagrams for reference. Review solutions and causes listed under the P2072, P2100, and C121C trouble codes sections of this forum. P2072 may contribute to setting P2100, which in turn can trigger C121C. Prioritize resolving the P2100 issue first. Common causes for P2100 include: - Open circuit in the throttle actuator wiring - Failed throttle actuator (mechanical or electrical) - Open circuit in the motor itself - PCM failure—less likely For more details, see: https://www.bbbind.com/p2100

Anonymous 2019-03-11 21:08

Thank you for the response—it provides a solid starting point. The scanner clearly reports 'P2100-Throttle actuator control motor circuit open,' confirming an open circuit in that system. I visited the site you referenced, but I couldn’t locate a wiring diagram specific to my 2006 Jeep WK Grand Cherokee Overland. After navigating through dropdown menus, I reached a section labeled 'Sorry, no sub-system found' under categories like exhaust pipe or Dodge Ram 1500. Based on this, I’m now considering that the C121C torque request error might be unrelated and caused by a separate sensor issue—since it persists but only appears intermittently, and the main symptoms have not returned after PCM removal.