P0603 on 2016-2018 Chevrolet Spark: Keep Alive Memory (KAM) Error Causes and Fixes

What's Unique About the 2016-2018 Chevrolet SPARK

For the 2016-2018 Spark, this code is typically a straightforward electrical issue, just as on other vehicles. However, it's notable that Chevrolet issued a recall (N192268880) and a TSB (#18089) for these model years because the Transmission Control Module (TCM) could have a memory fault *without* setting this code. While your vehicle *is* showing the code, this factory notice confirms that control module memory integrity is a known point of attention for this specific vehicle and its CVT transmission. This highlights the sensitivity of the module's memory systems on the Spark.

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
• No noticeable symptoms (very common)
• Rough or unstable idle, especially after starting or after a battery disconnect
• Hesitation during acceleration
• Harsh or erratic transmission shifting
• Reduced fuel economy
• Engine may be hard to start or won't start at all if the battery is the root cause.

Most Likely Causes

1. Recent Battery Disconnection or Replacement 🔴 High Probability → Shop Vehicle Battery This is the designed function of Keep Alive Memory. 🎬 Watch: Understanding how the Keep Alive Memory error code works. Disconnecting the power source erases the memory, which correctly sets the code on the next startup. This can also happen after a jump-start.
   How to confirm: Confirm if the battery has been disconnected for service, replacement, or went completely dead recently. The code will appear shortly after.
   Typical fix: Clear the code with a scanner. The code will also clear itself after several complete drive cycles as the PCM relearns its parameters.
   Est. part cost: $0
2. Weak or Failing Battery 🔴 High Probability → Shop Vehicle Battery A battery that provides low voltage during cranking can cause the PCM's memory to reset, triggering the code. The Spark uses a relatively small battery (Group Size H4/LN1) which can be sensitive to degradation.
   How to confirm: Test the battery voltage with a multimeter. It should be above 12.4V with the engine off. A professional load test at an auto parts store is the most definitive test.
   Typical fix: Replace the vehicle's battery.
   Est. part cost: $150-$250
3. Loose or Corroded Battery Terminals/Grounds 🟡 Medium Probability → Shop Vehicle Battery Corrosion or loose connections create high resistance, which can interrupt the stable power supply required by the PCM for its Keep Alive Memory. Owners on forums frequently report that a loose negative terminal is enough to trigger this code.
   How to confirm: Visually inspect the battery terminals for white or greenish corrosion. Physically attempt to twist the terminal clamps to check for tightness. Check the main chassis ground connection from the negative terminal for a clean, tight fit.
   Typical fix: Disconnect the battery (this will set the P0603 code if it isn't already present), clean the terminals and posts with a wire brush and baking soda solution, and securely re-tighten the clamps. 🎬 Watch: Step-by-step guide to cleaning corroded battery terminals and grounds.
   Est. part cost: $1-$10
4. Faulty Charging System ⚪ Low Probability A failing alternator can produce unstable voltage (too high or too low), which can corrupt the PCM's memory.
   How to confirm: With the engine running, test the voltage at the battery terminals. A healthy alternator should produce between 13.5V and 14.5V.
   Typical fix: Replace the alternator.
   Est. part cost: $200-$400

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): → Shop Engine Control Module (ECM) This is the 'textbook' cause but is rarely the actual problem. All power and ground issues must be exhaustively ruled out before condemning the PCM.
• Improperly Installed Aftermarket Electronics: Devices like remote starters or alarms can cause parasitic draw or voltage fluctuations, leading to a P0603 code. If the code appeared after an installation, this is a likely cause.
• Blown Fuse for PCM Memory: The PCM's KAM function is often protected by a dedicated fuse. If this fuse blows, the memory will be lost on every key cycle. Check fuses labeled 'PCM,' 'ECM,' or 'KAM' in the fuse box.

Diagnosis Steps

1. Ask the driver: Was the battery recently disconnected, replaced, or did it go dead? If yes, clear the code and drive the vehicle. The issue is likely resolved.
2. If the code returns, visually inspect the battery terminals for tightness and corrosion. Clean and tighten as necessary. Pay close attention to the negative terminal clamp, ensuring it cannot be moved by hand.
3. Test the battery's state of charge with a multimeter (should be >12.4V engine off) and have it professionally load-tested to confirm its health.
4. With the engine running, check the charging system voltage with a multimeter (should be 13.5V-14.5V).
5. Inspect the main ground strap from the battery to the chassis and engine block for a clean, tight connection. A poor ground is a common hidden cause.
6. Check the fuses for the PCM/ECM in the under-hood and interior fuse panels. Look for a fuse dedicated to module memory.
7. If all power and ground systems are confirmed to be in perfect working order and the code persists after being cleared, the issue may be an internal fault in the PCM, which requires professional diagnosis.

Parts You'll Likely Need

• Car Battery (OEM #88865429, 88866037, 88866291) — A weak or failing battery is the most common cause of a P0603 code after a simple battery disconnect.
  Trusted brands: ACDelco, DieHard, Interstate
  OEM price range: $200-$280
  Aftermarket price range: $150-$250

Technical Service Bulletins (TSBs) & Recalls

• 18089 / N192268880: Notes that on some 2016-2018 Sparks with the CVT, the TCM may fail to set code P0603 when a memory fault is present, and requires a software update. This confirms module memory sensitivity on this platform.

Platform-Specific Known Issues

• A recall (N192268880) and TSB (#18089) were issued for 2016-2018 Sparks because the Transmission Control Module (TCM) might NOT set a trouble code like P0603 when a memory checksum error occurs. The fix is a TCM software reprogram. While this addresses the *absence* of a code, it highlights that module memory issues are a known concern on this platform.

Mechanic-Grade Diagnostic Values

• ECM/PCM Power Supply Voltage (Open-Circuit) — expected: 12.6V or battery voltage. Failure: A reading of 0V indicates an open in the power or ground circuit. A reading significantly below battery voltage indicates high resistance (voltage drop).
• ECM/PCM Power Circuit Voltage Drop — expected: Less than 0.5V. Failure: A reading greater than 0.5V indicates excessive resistance in the power-side wiring, fuses, or connections between the battery and the ECM.
• ECM/PCM Ground Circuit Voltage Drop — expected: Less than 0.3V. Failure: A reading greater than 0.3V indicates excessive resistance in the ground-side wiring or at the ground point (e.g., G101).

Scan Tool Commands That Help

• GM GDS2 (Global Diagnostic System 2): Clear DTCs — Used after a repair (like tightening a battery terminal) to clear the P0603 code. GDS2 can confirm the code is cleared from all relevant modules.
• GM GDS2 (Global Diagnostic System 2): Module Diagnostics > Control Functions — Allows access to bidirectional controls and reset functions for specific modules, which can be useful if a module is not behaving correctly after a power loss event.
• GM GDS2 / Techline Connect (SPS2): PCM/ECM Programming and Setup — Required if the PCM is replaced. This process loads the correct software and VIN into the new module and is followed by an immobilizer relearn and crankshaft position variation learn.
• GM GDS2 (Global Diagnostic System 2): Crankshaft Position Variation Learn — This relearn procedure is often required after replacing the PCM or disconnecting power for an extended period to prevent misfire codes (like P1336) from appearing alongside or after resolving P0603.

Wiring & Ground Locations

• G101 — Located at the front of the engine, on the lower block.. This is a primary ground point for the Engine Control Module (ECM) and Transmission Control Module (TCM). A loose or corroded connection here can directly interrupt the power stability of the ECM, causing a P0603 code.
• G103 — Located at the left rear of the engine compartment on the cowl, above the brake booster.. This ground serves the Body Control Module (BCM) and the Data Link Connector (DLC). While not the primary ECM ground, a fault here can cause communication issues and other electrical gremlins that might occur alongside a P0603.
• Instrument Panel Fuse Box — Located on the driver's side of the instrument panel, behind a cover.. Contains fuses for various control modules. A blown fuse related to the ECM or BCM memory power feed could be a root cause.
• Serial Data Gateway Module (SDGM) — Located very high up in the driver's side dash, to the left of the steering column, held by two 10mm nuts facing forward. It is notoriously difficult to access.. This module acts as a go-between for all onboard modules. A failure here can cause widespread communication loss and various electrical issues, including symptoms that might be mistaken for a P0603 or PCM failure. A failure often presents with a 'Code 95' on the instrument cluster.

OEM Part Supersession History

• 12669908 → 12700116, 12676841 — Standard part revision and consolidation by the manufacturer.
  Heads up: The ACDelco E80 ECM is used across many GM vehicles. While physically similar, it must be programmed with the correct software for the 2016-2018 Spark using GM's Techline Connect (SPS2) service. Installing an unprogrammed or incorrectly programmed module will result in a no-start condition.