P0601 on 2008-2015 GMC Sierra 1500: Internal Control Module Failure Guide

What's Unique About the 2008-2015 Gmc SIERRA 1500

On this generation of GMC Sierra and its platform-mates (Silverado, Tahoe, Yukon), it's crucial to know that P0601 is not exclusive to the Engine Control Module (ECM). Manufacturer documents specifically mention this code can be set by the Transmission Control Module (TCM) as well. This makes proper diagnosis with a high-level scan tool that can communicate with individual modules essential to pinpoint which one has failed before ordering expensive parts.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Generation note: This range covers two generations of the GMC Sierra 1500: the GMT900 (2008-2013) and the K2XX (2014-2015). While the meaning of P0601 is the same for both, the specific ECM/TCM part numbers and locations may differ. The GMT900 trucks commonly use the E38 ECM, while the K2XX trucks use the E92 ECM. The diagnostic approach of verifying powers, grounds, and then identifying the failed module remains consistent across both generations.

Symptoms You May Notice

• Check Engine Light is on
• Service StabiliTrak message may appear
• Engine may stall or shut off while driving, sometimes with an "engine power refused" me 🎬 Watch: Troubleshooting a Silverado that stalls when hot with P0601.ssage
• Vehicle may not start or is hard to start
• Reduced engine power or "limp mode"
• Erratic or harsh transmission shifting
• ABS and Traction Control lights may illuminate
• Dimming or flickering interior/exterior lights
• Scan tool may not be able to communicate with the ECM

Most Likely Causes

1. Failed Engine Control Module (ECM) 🔴 High Probability → Shop Engine Control Module (ECM) Internal component failure is the most common reason for a checksum error. P0601 is often called the 'kiss of death' for a PCM because it almost always points to an unrecoverable internal fault. 🎬 Watch: A 2012 Silverado diagnosed with the P0601 'death code'. The diagnostic procedure for P0601 on these trucks often concludes with ECM replacement if the code persists after basic checks.
   How to confirm: After verifying all power and ground connections to the ECM are stable and providing correct voltage, and no software updates are available, a persistent P0601 code points to a failed ECM. A professional scan tool is needed to confirm the code is originating from the ECM and not another module.
   Typical fix: Replace the ECM and program the new unit to the vehicle's VIN and security system. This is often done with a pre-programmed unit from a specialty vendor or by a dealership.
   Est. part cost: $300-$800
2. Failed Transmission Control Module (TCM) 🟡 Medium Probability → Shop Transmission Assembly A GM Technical Service Bulletin (TSB PIP4653E) specifically notes that P0601 can be stored in the TCM on these trucks, which are commonly equipped with the 6L80 or 6L90 transmission featuring the T43 TCM.
   How to confirm: Use a scan tool capable of communicating with the TCM to see if the P0601 code is stored there. If the code is isolated to the TCM and power/grounds are good, the TCM is the likely culprit.
   Typical fix: Replace the TCM and perform the necessary programming and learn procedures. In some cases, the TSB suggests simply reprogramming the TCM with the latest calibration may resolve the issue.
   Est. part cost: $250-$700
3. Poor Power or Ground Connections ⚪ Low Probability These trucks are known for having critical ground straps that can corrode or break, causing voltage fluctuations that can upset control modules. A widely reported issue involves a ground strap from the chassis to the engine block on the driver's side, near the power steering lines and motor mount. Wiggling or cleaning this ground can sometimes make the P0601 code appear or disappear, confirming a connection issue.
   How to confirm: Perform a voltage drop test on the ECM/TCM power and ground circuits. Visually and physically inspect the main battery terminals and all major ground straps, especially the one on the driver's side of the engine block. A loose negative battery terminal is also a common cause of intermittent electronic issues.
   Typical fix: Clean the mating surfaces of the ground connection with a wire brush and re-secure it. If the strap is corroded or broken, replace it. Some owners add redundant ground straps to improve reliability.
   Est. part cost: $10-$150

Rare But Worth Checking

• Aftermarket Tuning or Programming: Improperly flashing the ECM with non-OEM performance tunes can sometimes corrupt the module's memory and trigger P06xx codes. There are owner reports of this code appearing after using handheld tuners like the DiabloSport InTune, where the code would temporarily disappear after flashing back to the stock tune, but ultimately the ECM required replacement.

Diagnosis Steps

1. Check the battery. Ensure it is fully charged (12.4-12.6V) and the terminals are clean and tight. A loose or corroded negative terminal is a common culprit for various electronic issues.
2. Scan for codes. Use a professional-grade scan tool to read the codes and, most importantly, identify which module (ECM, TCM, etc.) has stored the P0601 code. This is a critical step outlined in GM TSBs.
3. Inspect all power and ground connections. Pay special attention to the main ground strap located on the driver's side of the engine block, behind the power steering lines. 🎬 See this guide to locating and identifying critical engine grounds. Check for corrosion, looseness, or breakage. Wiggle the wires to see if it affects the code's presence.
4. Perform a voltage drop test on the identified module's power and ground circuits to ensure it's receiving a stable power supply. Unstable voltage can mimic an internal fault.
5. Check for available software updates. In rare cases, a manufacturer may release a software update to fix bugs that could cause false codes. TSB PIP4653E suggests a TCM reprogram might fix the issue if the code is stored there.
6. If all wiring, connections, and power/ground supplies are confirmed good, and the code returns immediately after clearing, the control module itself is faulty and must be replaced.

Parts You'll Likely Need

• Engine Control Module (ECM) (OEM #12612384, 12633238 (ACDelco E38 for GMT900)) — This is the most common cause of a P0601 code. The internal memory checksum process has failed, indicating the module is no longer reliable.
  Trusted brands: ACDelco (GM Genuine)
  OEM price range: $400-$800
  Aftermarket price range: $300-$600
• Transmission Control Module (TCM) (OEM #24256939 (ACDelco T43 for 6L80/6L90)) — GM TSBs confirm the TCM can also set this code. If diagnosis points to the TCM, it must be replaced or reprogrammed.
  Trusted brands: ACDelco (GM Genuine)
  OEM price range: $350-$700
  Aftermarket price range: $250-$500

Related Codes That Often Appear With This One

• P0606 — This code for 'ECM/PCM Processor Fault' is another type of internal module failure and can appear alongside P0601, reinforcing the diagnosis of a bad module.
• U-series codes (e.g., U0100, U0101) — If the failing module (ECM or TCM) starts to lose communication with other modules on the vehicle's network, communication (U-series) codes may also be stored, indicating a broader network problem originating from the faulty module.

Technical Service Bulletins (TSBs) & Recalls

• 05-06-04-060A: Information on control module DTCs P0601, P0602, P0603, P0604, P0606, P062F, P06F3, P1621 which can be shared in multiple modules. It stresses the importance of using a scan tool to identify which module set the code before starting diagnosis.
• PIP4653E: Information for vehicles with Malfunction Indicator Lamp on and DTCs P0601, P0603, P0604, P062F or P1621 stored in the Transmission Control Module. It advises that if the DTC is only in the TCM, a reprogram should be attempted.

Platform-Specific Known Issues

• Owner Experience: Intermittent Stalling and P0601: An owner of a 2008 Chevy Silverado reported the truck would intermittently shut off at low speeds, displaying an "engine power refused" message and code P0601. After a mechanic cleaned the throttle body with no success, the owner attempted to replace the ECM with an aftermarket unit but ran into programming issues, highlighting the difficulty of DIY replacement.
• Owner Experience: Aftermarket Tuner Complication: A user on the Diablosport forums detailed a lengthy battle with P0601 on their truck. The code would appear, causing the engine to shut down. Restoring the stock tune would temporarily fix the issue for hundreds or thousands of miles, but it would always return. Ultimately, the owner concluded the ECM was failing and the act of reflashing the memory was providing a temporary reset. The ECM was eventually replaced.
• Technician Confirmation: The 'Kiss of Death': On the ScannerDanner forum, a technician advises a GMC Yukon owner with a P0601 that it's the 'kiss of death' for the PCM and that replacement is the only fix after confirming good power and grounds. This reinforces the high probability of module failure.

Mechanic-Grade Diagnostic Values

• Battery Voltage (Key Off) — expected: 12.4V - 12.6V. Failure: Below 12.4V indicates a weak or discharged battery which can cause various electrical faults.
• Charging System Voltage (Engine Running) — expected: 13.5V - 14.5V. Failure: Voltage below 13.5V or spiking above 14.5V indicates an alternator or regulator issue that can damage control modules.
• Module Ground Circuit Resistance — expected: < 0.1 Ω. Failure: Resistance higher than 0.1 Ω between the module's ground pin and the chassis indicates a poor ground connection that needs to be cleaned or repaired.
• Module Power Feed Voltage Drop — expected: < 0.5 V. Failure: A voltage drop greater than 0.5V under load on the power feed wire to the ECM/TCM suggests a wiring issue that can starve the module for power.

Scan Tool Commands That Help

• GDS2 / Tech2: Module Programming (SPS - Service Programming System) — This function is required to flash a new or used ECM or TCM with the correct VIN-specific software and calibrations. Failure to program a replacement module will result in a no-start condition.
• GDS2 / Tech2: Vehicle Anti-Theft System (VATS) Relearn — After installing a newly programmed ECM, this procedure must be performed to synchronize the module with the vehicle's ignition keys and immobilizer system. The engine will not run until this is completed successfully.

Wiring & Ground Locations

• G104 — On the rear of the driver's side (left) cylinder head. A braided ground strap often connects from here to the firewall (G108).. This is a primary engine-to-chassis ground. Corrosion or breakage here is a widely reported cause of intermittent electrical issues, including module communication problems that can be misdiagnosed as a failed ECM.
• G108 — On the firewall in the left rear corner of the engine compartment, often to the right of the wiper motor grommet. It serves as the attachment point for the strap coming from G104 on the cylinder head.. This is the chassis-side termination for the critical G104 engine ground strap. A poor connection at this point can cause the same issues as a bad connection at the engine block.
• G101 / G106 — G101 is located on the lower front of the engine block. It grounds the ECM and TCM. It often jumpers to G106, located on the front center of the frame cross rail under the crank pulley.. These are the specific grounding points for the ECM and TCM. A voltage drop test should be performed referencing these points to ensure the modules have a solid ground path.
• G103 — On the front of the passenger side (right) cylinder head.. Another primary engine ground point. While less commonly cited for P0601 than the driver's side grounds, it is still a critical connection to inspect for tightness and corrosion.
• G218 (K2XX Models) — Inside the cab, behind the driver's side kick panel and under foam insulation.. On 2014-2015 models, this interior ground point is known to be problematic. The foam insulation can get caught under the nut, causing a poor connection and a host of electrical issues.

Real Owner Repair Stories

• YouTube user 'SOLVED' (2006 Chevrolet Trailblazer SS (Similar E38 ECM)) — Engine would run until it reached operating temperature (around 180°F), then stall and set code P0601.
  ❌ Tried (didn't work) Cleaning battery terminals.
  ✅ What actually fixed it After confirming the code returned after cleaning connections, the owner sent the original ECM to a specialist for repair/replacement. The replacement, pre-programmed ECM with a lifetime warranty resolved the stalling issue.
• 2CarPros Forum User (Chevrolet Colorado (Similar GM platform)) — Intermittent stall and no-start condition, 'reduced power' message on the cluster, and a persistent P0601 code.
  ❌ Tried (didn't work) Cleaning all ground points., Cleaning battery connections., Cleaning fuse box connections.
  ✅ What actually fixed it The user was advised that after exhausting all power and ground checks, the only remaining possibility was an internal failure of the ECM, requiring replacement. The thread confirms the diagnosis points squarely at the module itself once external factors are eliminated.

OEM Part Supersession History

• 24256939, 24256051, 24251412, and others → Multiple newer numbers including 24275873 — Internal revisions and software calibration updates for the T43 TCM used in 6L80/6L90 transmissions.
  Heads up: When replacing a T43 TCM, it is critical that the replacement module is programmed with the correct software for the vehicle's specific VIN. Simply installing a used module from another truck, even the same model year, will likely result in a no-start or no-communication condition.

Model Year Variations Within This Range

• 2008-2013 (GMT900): These models primarily use the E38 ECM. The most commonly cited ground fault location is the braided strap from the back of the driver's side cylinder head (G104) to the firewall (G108).
• 2014-2015 (K2XX): These models use the E92 ECM. In addition to engine bay grounds, they are known for problematic interior grounds, specifically G218 behind the driver's side kick panel, where foam insulation can interfere with the connection. Owners often add redundant ground wires to improve electrical system stability.