P0603 on 2011-2015 Chevrolet Camaro: Keep Alive Memory (KAM) Error Causes and Fixes

What's Unique About the 2011-2015 Chevrolet CAMARO

For the fifth-generation Camaro, the P0603 code is frequently a direct result of a battery issue or aftermarket tuning. A key factor is the battery's location in the trunk, which involves long cable runs and remote jump-start posts in the engine bay—all potential points for voltage drop or corrosion. The vehicle's various electronic modules, including the Transmission Control Module (TCM) as noted in GM's technical bulletins, are sensitive to voltage fluctuations. [Bulletin #PIP4653E] A weak battery, a jump start, or even disconnecting the battery for service can be enough to trigger this code. It's often considered a normal side effect of power loss rather than a sign of a major component failure.

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
• Rough or unstable idle
• Hesitation during acceleration
• Harsh or erratic transmission shifting
• Reduced fuel economy
• Difficulty starting the engine or slow cranking
• Intermittent stalling

Most Likely Causes

1. Weak, Failing, or Recently Disconnected Battery 🔴 High Probability → Shop Vehicle Battery The KAM system requires a constant, stable voltage. The Camaro's trunk-mounted battery means longer cables and more connections (including underhood jump posts) that can degrade over time. Any interruption, such as a battery replacement, a jump start, or a battery going dead, will erase this memory and set the code.
   How to confirm: Use a multimeter to test the battery voltage at the trunk terminals. It should be above 12.4 volts with the engine off and around 14.0-14.7 volts with the engine running. Many auto parts stores offer free battery and charging system load tests.
   Typical fix: Charge or replace the battery. Ensure the new battery is the correct type (AGM is common) and meets or exceeds OEM specifications (Group Size H7/94R is typical). 🎬 Watch this step-by-step guide to replacing your Camaro's trunk-mounted battery.
   Est. part cost: $180-$350
2. Loose or Corroded Battery Terminals/Cables 🟡 Medium Probability → Shop Vehicle Battery Corrosion or loose connections at the trunk battery terminals, the remote engine bay posts, or main chassis ground points 🎬 See how a dedicated ground harness can improve your electrical connections. can cause intermittent power loss to the control modules, even if the battery itself is healthy.
   How to confirm: Visually inspect the battery terminals in the trunk, the red positive jump post cover in the engine bay, and the main chassis ground connection for corrosion (white or greenish powder) or looseness. Try to wiggle the terminals by hand.
   Typical fix: Disconnect the battery (negative first), clean the terminals and cable ends with a wire brush and a baking soda/water solution, and re-tighten them securely. Apply a terminal protectant spray.
   Est. part cost: $5-$20
3. Faulty Alternator or Charging System Issue ⚪ Low Probability → Shop Alternator An alternator that is failing may not provide a consistent voltage while the car is running, leading to electrical issues and potentially draining the battery, which triggers the P0603 code.
   How to confirm: With the engine running, a multimeter should read approximately 14.0-14.7 volts at the battery terminals. A reading below 13.5V or fluctuating wildly suggests a charging system problem.
   Typical fix: Replace the alternator.
   Est. part cost: $200-$450
4. Aftermarket Engine Tuning ⚪ Low Probability Flashing the PCM with an aftermarket tune can cause this code. Any voltage interruption during programming can cause issues. A corrupted file or an unstable power supply during the flash can trigger P0603.
   How to confirm: Determine if the vehicle has been tuned. If so, the code may have appeared shortly after the tune was applied. The only way to be certain is to flash the PCM back to the stock factory tune.
   Typical fix: Ensure a stable power supply (battery charger) is used during flashing. Re-flash the PCM with a corrected tune or return it to the stock configuration. Consult the tuning software provider for support.
   Est. part cost: $0-$200

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): → Shop Engine Control Module (ECM) This is extremely rare. Before condemning the PCM, all other power, ground, and charging system issues must be exhaustively ruled out. The P0603 code is far more likely to be caused by an external power issue than an internal PCM fault.
• Parasitic Electrical Drain: An improperly installed aftermarket accessory (like a stereo or alarm) or a faulty module can slowly drain the battery overnight, causing a low voltage condition on startup that triggers P0603. A sustained draw above 50mA after modules go to sleep is a sign of a problem.
• High Resistance in Communication Enable Circuit: A known GM issue involves high resistance or an open in the 'Communication Enable' circuit (Circuit 5986), which can prevent modules from waking up or communicating properly, sometimes leading to memory-related codes. This issue is often traced to wiring under the driver's or passenger's sill plates.

Diagnosis Steps

1. Scan for any other DTCs. Note them and address them first if they relate to the charging system or other modules.
2. Ask the driver if the battery was recently replaced, disconnected, or jump-started. If so, the code is likely a normal consequence. Clear the code and see if it returns after a few drive cycles.
3. Visually inspect the battery terminals and main ground connections in the trunk for looseness or corrosion. Also inspect the remote positive and negative jump-start posts in the engine bay. Clean and tighten as needed.
4. With the engine off, use a multimeter to test battery voltage at the trunk terminals. A healthy, fully charged AGM battery should read around 12.6V-12.8V.
5. Start the engine and measure the voltage at the battery terminals. It should be between 14.0V and 14.7V, indicating a healthy alternator.
6. If the battery and alternator test good but the battery dies over time, perform a parasitic draw test. 🎬 Watch this simple demonstration on how to test for parasitic draw. After all modules go to sleep (this can take up to 2 hours), the draw should be under 50mA, ideally closer to 20-30mA.
7. If the vehicle has an aftermarket tune, consider flashing it back to stock to see if the code disappears.
8. Only after all power and ground circuits have been proven to be 100% stable should a faulty PCM be considered.

Parts You'll Likely Need

• Automotive Battery (AGM) (OEM #ACDelco Gold 94RAGM (Group Size H7/94R)) — This is the most common cause, as the code is triggered by a loss of constant power to the vehicle's computer memory. An AGM (Absorbent Glass Mat) battery is often recommended for these vehicles.
  Trusted brands: ACDelco, DieHard, Optima, Odyssey
  OEM price range: $250-$350
  Aftermarket price range: $180-$300
• Battery Terminal Cleaner and Protector Kit — Fixing loose or corroded battery terminals is a very common, low-cost fix for the power interruptions that cause P0603.
  Trusted brands: CRC, NOCO
  OEM price range: $10-$20
  Aftermarket price range: $5-$15

Related Codes That Often Appear With This One

• P0601, P0602, P0604, P0606, P1621 — GM Technical Service Bulletin #05-06-04-060A explicitly states that P0603 can be set along with these other internal module codes across multiple different control modules, often pointing to a shared electrical issue or a programming event.

Technical Service Bulletins (TSBs) & Recalls

• Bulletin #05-06-04-060A: Information on control module Diagnostic Trouble Code(s) (DTC)(s) P0601, P0602, P0603, P0604, P0606, P062F, P06F3, P1621 which can be shared in multiple modules.
• Bulletin #PIP4653E: Provides information for vehicles with a Malfunction Indicator Lamp on and DTCs P0601, P0603, P0604, P062F or P1621 stored in the Transmission Control Module.

Platform-Specific Known Issues

• Trunk-Mounted Battery: The battery is located under the spare tire in the trunk, not under the hood. This requires removing the trunk floor and spare to access it. If the battery is dead, the trunk may need to be opened with the manual release inside the car.
• Remote Jump-Start Posts: Because the battery is in the trunk, there are dedicated posts in the engine bay for jump-starting. These posts and their connections are an additional point of failure to check for corrosion or looseness.
• GM TSB #05-06-04-060A: Acknowledges that codes like P0603 can be set in multiple modules and provides diagnostic information, cautioning against immediate module replacement.
• TSB #PIP4653E: Specifically notes that P0603 can be found in the Transmission Control Module (TCM), which can lead to shifting-related symptoms.

Mechanic-Grade Diagnostic Values

• Parasitic Current Draw — expected: Less than 50 milliamperes (0.050A). Failure: A sustained reading above 50mA after all modules have entered sleep mode (can take up to 2 hours) indicates a parasitic draw is draining the battery.
• Battery Voltage (Engine Off) — expected: Greater than 12.4 Volts (12.6V+ for a fully charged battery). Failure: A reading below 12.4V indicates a discharged or failing battery that cannot maintain the Keep Alive Memory.
• Charging System Voltage (Engine Running) — expected: Approximately 14.0 - 14.7 Volts. Failure: A voltage reading below 13.5V or one that fluctuates wildly indicates a failing alternator that cannot properly charge the battery and power the modules.

Scan Tool Commands That Help

• GM GDS2 / Tech2Win: Clear DTCs — After performing a repair (e.g., replacing the battery, cleaning grounds), this function is used to erase the P0603 code from the module's memory. The vehicle should then be driven to see if the code returns.
• N/A - Manual Procedure: Idle Relearn Procedure — After any event that causes a P0603 (like disconnecting the battery), the PCM's learned values are lost. Allowing the engine to idle for 10-15 minutes after startup lets the system begin to relearn idle control and other parameters.

Wiring & Ground Locations

• Engine Block Grounds — Multiple locations on the engine block and back of the cylinder heads. A key ground strap runs from the engine block to the chassis frame.. The ECM/PCM is grounded via the engine block. High resistance or a loose connection at these points can cause unstable voltage to the computer, directly triggering a P0603 code, especially during high-current events like starting the engine when hot.
• G103 — Located on the cowl in the engine compartment, typically above the brake booster on the driver's side.. This is a critical ground point for the Body Control Module (BCM) and the Data Link Connector (DLC). A poor connection here can cause a wide range of communication and electrical issues, including problems with modules not entering sleep mode, leading to parasitic draw.
• Main Battery Ground — In the trunk, where the main negative battery cable connects to the vehicle's chassis, near the battery.. This is the primary ground for the entire vehicle's electrical system. Corrosion or looseness here will cause system-wide voltage problems and is a direct cause of P0603.

Real Owner Repair Stories

• Gen5DIY.com and Camaro forum discussions (2014-2015 Chevrolet Camaro (V8 models particularly noted)) — Engine cranks slowly or hesitates to start only when hot. The car starts fine when cold. P0603 code may be present.
  ❌ Tried (didn't work) Replacing the battery., Replacing the starter., Testing the alternator (which checked out fine).
  ✅ What actually fixed it Installing an additional, heavy-gauge ground strap directly from the engine block (or bellhousing) to the chassis. This provided a more robust ground path for the starter and engine electronics, resolving the voltage drop that occurred due to heat-soak increasing resistance in the factory grounds.

"I Checked Everything" — The Actual Cause

• For code P0603, the electrical equivalent of a 'smoke test clean' scenario is when the battery and alternator both test perfectly fine, yet the code persists or the battery continues to die. The actual cause in these cases is almost always either a hidden parasitic draw from a module that isn't going to sleep, or high resistance in a main ground wire (especially the engine-to-chassis ground) that only becomes problematic when the engine bay is hot.

Model Year Variations Within This Range

• 2013-2015: The introduction of the MyLink touchscreen audio system in 2013 added a complex new module to the vehicle's electrical system. A malfunctioning MyLink unit can fail to shut down properly, creating a source of parasitic draw that would not be present on 2011-2012 models with the base radio.
• 2012-2015: The V6 engine was updated from the LLT to the LFX in 2012. While the core cause of P0603 remains the same, the physical routing of some wires and the specific location of engine ground points may differ slightly between the two engine designs.