P0604 on 2011-2015 Chevrolet Volt: Power Inverter Module Failure and Fixes

What's Unique About the 2011-2015 Chevrolet VOLT

Unlike a conventional gasoline car where a P0604 might mean a faulty and relatively inexpensive Engine Control Module (ECM), on the first-generation Volt, it signifies a failure in a core component of the high-voltage hybrid drive system. Manufacturer Technical Service Bulletin #PIP5463A explicitly links this code to a loss of propulsion and mandates the replacement of the entire Power Inverter Module. This is not a simple software glitch or a minor electronic fault; it's a major hardware failure unique to the vehicle's hybrid architecture. Further TSBs like PIP5320E put a restriction on the part, requiring dealer technicians to contact GM's Technical Assistance Center before ordering a replacement, underscoring the seriousness and frequency of the failure.

Diagnostic Flowchart

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

Symptoms You May Notice

• Sudden loss of propulsion while driving
• Malfunction Indicator Lamp (Check Engine Light) is on
• Vehicle may not start or enter a ready-to-drive state
• Error messages on the driver information center related to the hybrid system, such as "Propulsion Power Reduced".
• Clunky, jerking motion when regenerative braking is active, which may precede total failure.
• Vehicle may die at a stop and refuse to restart.

Most Likely Causes

1. Failed Power Inverter Module (PIM) 🔴 High Probability As documented in TSB #PIP5463A and part restriction bulletin PIP5320E, this module is a known high-failure component on this platform that specifically triggers the P0604 code in the HPCM. The failure is an internal hardware fault within the module's RAM.
   How to confirm: A professional scan tool must be used to confirm that DTC P0604 is stored in the Hybrid Powertrain Control Module (HPCM). The presence of this code, especially when accompanied by a loss of propulsion, is considered definitive evidence of PIM failure according to GM's service literature.
   Typical fix: Replace the Power Inverter Module (also called the Drive Motor Generator Control Module) and program the new unit to the vehicle.
   Est. part cost: $400-$3500

Rare But Worth Checking

• Low 12V Battery Voltage: A failing 12V auxiliary battery can cause a host of unpredictable electronic issues and error codes in modern vehicles, including control module communication faults. While unlikely to be the root cause if P0604 is the primary code and symptoms are severe, it's a simple and inexpensive item to check first, as a weak 12V battery is a known issue on Volts. 🎬 See how a weak 12V battery causes mysterious hybrid codes A full disconnect and proper recharge of the 12V battery has been reported to resolve P0604 on other GM vehicles.
• Wiring Harness or Connector Issue: Damage to the wiring or a poor connection at the Power Inverter Module could theoretically cause communication and internal errors. This is unlikely but should be visually inspected during diagnosis, checking for corrosion or loose pins.

Diagnosis Steps

1. Confirm the customer complaint of a check engine light and/or loss of propulsion.
2. Scan all vehicle control modules with a professional-grade scan tool. Do NOT clear codes, as GM's diagnostic procedure for this part requires reviewing all stored data.
3. Specifically check for DTCs in the Hybrid Powertrain Control Module (HPCM / T6 Power Inverter Module).
4. If P0604 is present, reference GM Technical Service Bulletin #PIP5463A as the primary diagnostic path.
5. Check the state of health of the 12V auxiliary battery and test its voltage under load to rule out simple power supply issues, which are a known cause of multiple, confusing codes on the Volt. Ensure ground resistance is below 0.1 Ω.
6. Visually inspect the wiring harness and connectors leading to the Power Inverter Module for any signs of damage, corrosion, or looseness. Specifically check the gray X1 and black X2 low-voltage connectors.
7. Following the guidance of TSBs #PIP5463A and #PIP5320E, the diagnosis is a failed Power Inverter Module. The technician may need to contact GM Technical Assistance Center (TAC) to review the case before a replacement part is ordered.
8. Proceed with replacement and reprogramming of the PIM.
🎬 Watch: Step-by-step guide to replacing the control module

Parts You'll Likely Need

• Power Inverter Module (PIM) (OEM #24285395 (superseded by 24292221), 24275450, 24286539) — This is the component that fails internally, triggering the P0604 code and causing the loss of propulsion, as identified by GM's own service bulletins. It is also referred to as the Drive Motor Generator Control Module. 🎬 Watch: A detailed look at the Volt's Power Inverter Module
  Trusted brands: ACDelco (OEM)
  OEM price range: $2500-$4000
  Aftermarket price range: $400-$1500 (Used or Remanufactured)

Related Codes That Often Appear With This One

• P0AC4 — This code indicates a request from the Hybrid Powertrain Control Module to illuminate the check engine light, often appearing alongside more specific fault codes like P0604. It is frequently cited by owners experiencing PIM failure.
• P0A46, P1B04 — These codes were reported by an owner in conjunction with P0AC4 when their Power Inverter Module failed, suggesting they can be part of the fault cascade.
• P0601, P0602, P0603, P0606 — These are all related internal control module error codes. TSB #05-06-04-060A notes that these codes can be set across various modules, indicating a family of electronic self-check failures.

Technical Service Bulletins (TSBs) & Recalls

• PIP5463A: Addresses a loss of propulsion with DTC P0604 set, instructing technicians to replace the Power Inverter Module.
• 05-06-04-060A: An informational bulletin that groups P0604 with other internal control module error codes that can appear in various modules.
• PIP5320E: Places the Drive Motor Generator Control Module (PIM) on a part restriction, requiring TAC involvement for replacement, and lists relevant part numbers.

Platform-Specific Known Issues

• A known failure of the Power Inverter Module is documented in TSB #PIP5463A, which directly links it to code P0604 and a potential loss of propulsion.
• GM issued TSB #PIP5320E to place the PIM on a part restriction, requiring dealers to consult with the Technical Assistance Center before replacement, indicating a tracked quality issue.

Mechanic-Grade Diagnostic Values

• Ground circuit resistance — expected: Below 0.1 Ω. Failure: A reading higher than 0.1 Ω indicates excessive resistance in a ground circuit, which can cause unpredictable module behavior.
• 12V Battery Voltage (cranking) — expected: Above 9.6V. Failure: Voltage dropping below 9.6V during engine crank can cause control modules to reset or store false memory error codes like P0604.

Hidden / Shadow Codes Worth Checking

• Symptom Codes: GM uses additional single-byte codes that provide more specific details about a primary DTC. For P0604, a symptom code could further specify the nature of the internal RAM error. (see via These are visible in the DTC data when using dealer-level scan tools like a GM MDI with GDS2 software. TSB #PIP5320E specifically instructs technicians to record these codes.)

Scan Tool Commands That Help

• GM SPS (Service Programming System): Module Programming/Setup — This function is required after installing a new Power Inverter Module (PIM) to load the correct software and VIN, and to configure it to the vehicle. This can be done with a J2534 passthrough device (like a VXDiag VCX Nano) and a paid subscription to GM's TIS2Web/SPS.
• GDS2: Capture Info / DTC Snapshot — Before clearing any codes, this function must be used to save all freeze frame and failure records. TSB #PIP5320E explicitly states not to clear DTCs and to save this data for review by the GM Technical Assistance Center before a PIM replacement is authorized.

Wiring & Ground Locations

• Power Inverter Module (PIM) — Located on the driver's side of the engine compartment, mounted on top of the transmission.. This is the module that fails, causing code P0604. Knowing its location is the first step for visual inspection and replacement.
• PIM Connector X1 (Gray) & X2 (Black) — These are the two low-voltage signal connectors on the PIM.. A poor connection, corrosion, or wiring damage at these connectors could theoretically cause communication or internal module errors. A visual inspection is a key diagnostic step.
• PIM Connector X3 — The high-voltage DC connector on the PIM, fed by two large orange cables from the main battery.. While less likely to cause a RAM error, any issue with high-voltage connections is a major safety concern and should be inspected by a qualified technician during service.
• G101 / G102 — These are common engine and chassis ground locations in GM vehicles, typically on the engine block, firewall, or frame rails.. A poor main ground connection can cause low voltage or voltage instability at various control modules, including the PIM, potentially leading to memory-related fault codes like P0604.

Real Owner Repair Stories

• Reddit r/volt user (2013 Chevrolet Volt) — While driving, experienced 'clunky jerking' during regenerative braking, followed by a loss of propulsion. Check engine light on.
  ❌ Tried (didn't work) Getting a quote from a second dealer after the first was deemed too high.
  ✅ What actually fixed it The confirmed diagnosis from two separate dealers was a failed Power Inverter Module. The final fix was replacing the PIM. The owner was quoted $4300. The codes present were P0AC4, P0A46, and P1B04.
• Chevy HHR forum user (Chevrolet HHR (non-hybrid, but GM platform)) — No crank, no start condition after the 12V battery was drained completely. Check engine light on with code P0604.
  ❌ Tried (didn't work) Jump starting the vehicle., Using a slow, low-amperage float charger to recharge the battery while connected to the car.
  ✅ What actually fixed it The owner, an electrical engineer, disconnected the 12V battery from the vehicle entirely and charged it fully with a proper charger. After reinstalling the fully charged battery, the car started immediately and the P0604 code was gone. The theory was that the slow discharge/recharge cycle corrupted the control module's RAM, which was resolved by a complete power cycle with a healthy battery.

OEM Part Supersession History

• 24275450, 24286539 → Unknown — These part numbers are explicitly named in TSB #PIP5320E as being placed on restriction, confirming they are valid PIM part numbers for this vehicle. Pass 2 data suggests 24285395 was superseded by 24292221.

Model Year Variations Within This Range

• 2011-2015: The P0604 code pointing to PIM failure is a known issue for the entire first generation of the Chevrolet Volt. The second generation, starting in 2016, uses a different powertrain design, including a lighter, redesigned drive unit and inverter.