P0601 on 2015-2018 GMC Yukon: Internal Module Failure Causes and Fixes

What's Unique About the 2015-2018 Gmc YUKON

The 2015-2018 GMC Yukon belongs to the K2UG platform. For this generation, General Motors issued several Technical Service Bulletins (TSBs) related to P0601. These bulletins emphasize that while the code often means the ECM has failed, technicians should first investigate external factors like poor electrical connections, grounds, and power supply issues. A key point for these trucks is that the P0601 code can also be stored in the Transmission Control Module (TCM), not just the ECM, which can complicate diagnosis if not properly investigated with a professional scan tool that can read all modules.

Diagnostic Flowchart

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

Symptoms You May Notice

• Check Engine Light is on
• Vehicle may not start or is hard to start
• Engine may stall intermittently or shut down while driving
• "Reduced Engine Power" message on the dashboard
• "Service Stabilitrak" message on the dashboard
• Erratic transmission shifting
• Unstable or rough idle

Most Likely Causes

1. Failed Engine Control Module (ECM) 🔴 High Probability → Shop Engine Control Module (ECM) The P0601 code is the direct definition of an internal ECM memory failure. The ACDelco E92 ECM used in these trucks can fail due to age, heat cycles, or internal component degradation. After ruling out external electrical issues, the module itself is the most common point of failure.
   How to confirm: After verifying all power and ground connections to the module are good per TSB PIP5609, if the code returns immediately after being cleared, the ECM is condemned. A professional shop can attempt to re-flash the software, but if that fails or the code returns, replacement is necessary.
   Typical fix: Replace the Engine Control Module and program the new unit to the vehicle's VIN.
   Est. part cost: $400-$800
2. Poor Power or Ground Connections 🟡 Medium Probability GM TSB #PIP5609 specifically advises technicians to inspect the ECM's electrical connections and verify proper power before replacement. These trucks are sensitive to voltage fluctuations, and a bad ground or loose battery connection can mimic internal module failure. Key ground points to inspect include G101 (engine block) and G103 (cowl/firewall).
   How to confirm: Visually inspect and physically wiggle all battery terminals, the main engine-to-chassis ground strap, and the ECM connectors. Perform a voltage drop test on the power and ground circuits to the ECM to check for high resistance. A resistance of greater than 5 ohms on a ground circuit is indicative of a problem. Cleaning and tightening these connections is a crucial first step.
   Typical fix: Disassemble, clean, and tighten all corroded or loose ground straps and power connections. Replace faulty battery cables if necessary.
   Est. part cost: $10-$100
3. Low Battery Voltage or Failing Alternator 🟡 Medium Probability → Shop Alternator An aging battery or a failing alternator can provide unstable voltage, especially during startup. This can corrupt a module's self-test procedure and trigger a false P0601 code. A user on a Tahoe/Yukon forum with a 2017 model resolved a 'Reduced Engine Power' message simply by replacing an old battery. 🎬 See how a weak battery causes Reduced Engine Power messages.
   How to confirm: Test the battery with a load tester to ensure it's healthy (should be above 12.4V at rest). With the engine running, check the alternator output with a multimeter (should be 13.5V-14.5V).
   Typical fix: Replace the battery and/or alternator.
   Est. part cost: $150-$500
4. Failed Transmission Control Module (TCM) ⚪ Low Probability → Shop Transmission Assembly GM TSB #PIP4653E explicitly states that P0601 can be stored in the TCM on these vehicles. This can cause shifting problems and illuminate the check engine light, leading to a misdiagnosis of the ECM.
   How to confirm: Use a professional scan tool that can communicate with all vehicle modules (ECM, TCM, BCM, etc.) to verify if the P0601 code is stored in the TCM instead of the ECM. This is a critical step before ordering parts.
   Typical fix: Replace the Transmission Control Module and program it to the vehicle.
   Est. part cost: $250-$500

Rare But Worth Checking

• Aftermarket Performance Tune: If the ECM has been reprogrammed with an aftermarket tune (e.g., from HP Tuners), a corrupted file or an interrupted flashing process can cause a checksum error. Reverting to the factory GM software calibration is a key diagnostic step to rule this out.
• Water Intrusion: If water has penetrated the ECM housing or its connectors, it can cause short circuits and corrupt the module's internal memory. This requires inspecting the module and its harness connectors for signs of moisture or corrosion.

Diagnosis Steps

1. Check the battery's state of charge and health with a load tester. Ensure it is above 12.4 volts and holds a load.
2. Start the engine and verify the alternator is charging correctly, between 13.5 and 14.5 volts.
3. Inspect all battery terminals and main ground cables (battery-to-chassis, engine-to-chassis) for corrosion or looseness. Disassemble, clean, and tighten as needed.
4. Following TSB #PIP5609, inspect the electrical connectors at the control module (ECM/TCM) for damage, corrosion, or poor terminal tension.
5. Use a professional-grade scan tool to determine which module (ECM or TCM) has stored the P0601 code. This is a critical step per TSB #PIP4653E.
6. Clear the codes and perform a key cycle or short test drive. If the P0601 code returns immediately, the module itself is almost certainly faulty.
7. If the vehicle has an aftermarket tune, attempt to flash it back to the stock GM calibration.
8. If all external wiring, power, and grounds are confirmed to be good, the faulty control module must be replaced.
9. The new module must be programmed to the vehicle by a dealer or qualified independent shop using GM-approved software.
🎬 Watch: A guide to programming modules with GM SPS2 software.

Parts You'll Likely Need

• Engine Control Module (ECM) (OEM #12672535 (Varies by year/engine, example for E92)) — This is the most common cause of a P0601 code once external electrical issues have been ruled out. The code indicates a fatal internal memory error within the module, which is typically an ACDelco E92 type for this vehicle.
  Trusted brands: ACDelco (OEM), Cardone (Remanufactured), FS1
  OEM price range: $450-$800
  Aftermarket price range: $350-$600

Related Codes That Often Appear With This One

• P0603 — This code for 'Internal Control Module Keep Alive Memory (KAM) Error' is also related to module memory and can be set by similar power supply issues.
• P0604 — This code for 'Internal Control Module Random Access Memory (RAM) Error' points to a different type of internal memory fault but often has the same root causes.
• P1621 — This is a GM-specific code for 'Control Module Long Term Memory Performance' and is often seen alongside P0601, as mentioned in TSB #PIP4653E.

Technical Service Bulletins (TSBs) & Recalls

• PIP5609: Advises checking ECM electrical connections and power for codes P0601-P0606. Explicitly states that low voltage or momentary loss of power can cause these DTCs.
• 05-06-04-060A: Informs that codes like P0601 can be set in multiple different control modules.
• PIP4653E: Notes that P0601 can be stored in the Transmission Control Module (TCM) and to verify which module set the code before repair. Recommends reprogramming the TCM as a first step.

Platform-Specific Known Issues

• TSB #PIP5609 advises checking the ECM's electrical connections and power supply before replacing the module for a P0601 code. This bulletin explicitly lists the 2016-2018 Yukon.
• TSB #05-06-04-060A is an informational bulletin noting that P0601 can be shared across multiple modules.
• TSB #PIP4653E is critical, as it documents that P0601 can be stored in the Transmission Control Module (TCM), not just the ECM, which is essential for correct diagnosis. The first step it recommends is attempting to reprogram the TCM before replacement.

Mechanic-Grade Diagnostic Values

• ECM Battery Positive Voltage — expected: Should be within 1V of battery voltage.. Failure: Voltage below 10.5V can trigger module errors. A significant drop from battery voltage indicates high resistance in the power feed circuit.
• ECM Ground Circuit Resistance — expected: Less than 5.0 Ω to a known good ground.. Failure: Resistance greater than 5.0 Ω indicates a poor ground connection that can cause intermittent module resets and false codes.
• ECM Connector Pin Voltage (Key On, Engine Off) — expected: 12V+ at Pin 51 (Run/Crank Ignition 1 Voltage) and Pin 52 (Battery Positive Voltage) on the X1 connector.. Failure: Low or no voltage at these pins points to a wiring or fuse block issue, not a faulty ECM.

Scan Tool Commands That Help

• GDS2 (Global Diagnostic System 2): Module Diagnostics / DTC Display — Used to confirm which specific module (ECM, TCM, BCM, etc.) has stored the P0601 code. This is a critical first step as TSBs indicate the fault could be in the TCM.
• SPS2 (Service Programming System 2) via Techline Connect: Replace and Program Controller — This function is required after physically installing a new ECM or TCM. It downloads the correct GM calibration file for the vehicle's VIN and options, and programs it to the new module.
• SPS2 (Service Programming System 2) via Techline Connect: Configuration & Setup — After programming a new module, a setup or configuration procedure must be run. This teaches the module about the specific configuration of the truck and learns values from other sensors, such as the steering angle sensor or brake pedal position sensor. Skipping this step can set other codes.

Wiring & Ground Locations

• G101 / G106 — G101 is located on the engine block. It is often tied to G106, which is on the front center of the frame cross rail, under the crank pulley.. This is a primary ground for the Engine Control Module and Transmission Control Module. A poor connection here can cause low voltage and trigger a P0601.
• G103 — Located on the cowl at the left (driver's side) rear of the engine compartment, often above the brake booster.. This is a major ground point for the Body Control Module (BCM), Instrument Panel Cluster (IPC), and Data Link Connector (DLC). While not a direct ECM ground, a fault here can cause widespread communication issues that could potentially mimic a module failure.
• ECM X1 Connector — This is the main connector at the Engine Control Module.. TSB #PIP5609 specifically calls for inspecting this connector. Key pins for testing are Pin 51 (Ignition Voltage), Pin 52 (Battery Voltage), and Pin 73 (Ground).

Real Owner Repair Stories

• Tahoe Yukon Forum (2014 GMC Yukon SLT 5.3L (K2UG Platform Precursor)) — Vehicle died while idling, displayed "Service Stabilitrak" errors, and set code P0601. It would not restart until the codes were cleared, then would die again after about 15 minutes.
  ❌ Tried (didn't work) Initial advice was to check all power and ground cables.
  ✅ What actually fixed it The code was temporarily reset by wiggling the ground wires near the driver's side motor mount (G104 area on that specific platform). The permanent fix was disassembling, cleaning, and re-securing that specific ground connection.

OEM Part Supersession History

• 12656993 → Not explicitly stated, but this is a common number for 2015-2016 models. — General software/hardware updates.
  Heads up: When replacing an ECM, the Service Part Number (the large number on the sticker) must be compatible. The new module must be programmed with GM's SPS2 software to load the correct VIN and vehicle calibrations.
• 12692067 → Not explicitly stated, but this is a common number for 2015 models with the 6.2L engine. — General software/hardware updates.
  Heads up: Using a module from another vehicle without reprogramming will result in a no-start condition and multiple communication codes, as the VIN and security data will not match.