Encountering OBD2 codes after repairing a flood-damaged vehicle can be perplexing. This situation is exactly what happened with a 2015 Chevy Traverse LT, and understanding these codes is the first step towards resolving them. After purchasing a salvaged Traverse that had been flooded and initially wouldn’t start, the vehicle was revived, but now presents with a check engine light and a set of persistent OBD2 codes. Let’s delve into these codes and explore potential troubleshooting steps for a 2015 Chevy Traverse in a similar predicament.
The initial diagnostic scan revealed four specific codes, all marked as “permanent”:
- P135A – Ignition Coil Supply Voltage Circuit Bank 1
- P135B – Ignition Coil Supply Voltage Circuit Bank 2
- P1682 – Ignition 1 Switch Circuit 2
- P0443 – Evaporative Emission (EVAP) Purge Solenoid Valve Control Circuit
These codes collectively point towards electrical system issues, which is highly plausible given the vehicle’s history of flood damage. The fact that the fuse box was found packed with mud further strengthens this suspicion. Let’s break down each code to understand the potential problems.
P135A & P135B: Ignition Coil Supply Voltage Circuit Banks 1 & 2
These two codes indicate problems within the voltage supply circuits for the ignition coils, specifically for Bank 1 and Bank 2 of the engine. In a 2015 Chevy Traverse, which likely has a V6 engine, it’s crucial to understand engine bank layout to properly diagnose. Essentially, the engine is divided into two banks, and these codes suggest that the coils on both banks are not receiving the correct voltage.
Possible causes related to flood damage include:
- Corrosion in Connectors and Wiring: Water damage can lead to corrosion in electrical connectors and wiring harnesses that supply power to the ignition coils. This corrosion can increase resistance, reducing voltage supply.
- Fuse Box Issues: As mud was found in the fuse box, there could be residual corrosion or damage affecting the fuses and relays related to the ignition coil circuits, even after cleaning.
- Relay Problems: Relays control the power supply to various circuits. A damaged or corroded relay for the ignition system could cause these voltage supply issues. The original poster mentioned a clipped “CRNK” relay, highlighting potential relay-related problems.
- ECM/PCM (Engine/Powertrain Control Module): While less likely initially, if the ECM/PCM was submerged, it could have sustained internal damage affecting its ability to properly control the ignition coil voltage.
P1682: Ignition 1 Switch Circuit 2
This code, P1682, indicates a problem with the Ignition 1 Switch Circuit 2. This circuit is critical for providing power to various engine management systems when the ignition switch is in the ‘Run’ position. Floodwater intrusion can severely impact the ignition switch and its associated wiring.
Potential causes in a flood-damaged context:
- Ignition Switch Corrosion: The ignition switch itself might have suffered corrosion, leading to intermittent or failed circuit operation.
- Wiring Harness Damage: The wiring from the ignition switch to the ECM/PCM and other components could be damaged or corroded, disrupting the signal.
- Fuse/Relay Issues: Similar to the ignition coil codes, fuses and relays in the Ignition 1 Switch Circuit 2 could be corroded or malfunctioning.
P0443: Evaporative Emission (EVAP) Purge Solenoid Valve Control Circuit
The P0443 code points to a problem in the control circuit for the EVAP purge solenoid valve. This valve is part of the evaporative emissions system, which prevents fuel vapors from escaping into the atmosphere. While the original poster tested the solenoid itself and found it clicking, the issue lies within the control circuit.
Flood-related causes could be:
- Purge Solenoid Connector/Wiring: Corrosion in the connector or wiring leading to the purge solenoid valve could disrupt the control signal from the ECM/PCM.
- ECM/PCM Control Issue: Less likely but possible, the ECM/PCM might have an issue in its output signal to control the EVAP purge solenoid.
Addressing “Permanent” Codes and Next Steps
The OBD2 reader indicating “permanent” codes simply means these are confirmed fault codes that the system recognizes as currently active or recently resolved but require certain drive cycles to fully clear. They are not necessarily un-clearable without significant repair, nor do they automatically mean a new ECM is needed.
Troubleshooting Steps:
- Thoroughly Inspect Wiring and Connectors: Begin by meticulously inspecting all wiring harnesses and connectors in the engine bay, especially those related to the ignition system, ignition switch, and EVAP purge solenoid. Look for signs of corrosion, water damage, or loose connections. Clean any corrosion with electrical contact cleaner.
- Check Fuses and Relays Again: Re-examine all fuses and relays in the fuse box, even those that were previously cleaned. Ensure they are properly seated and not corroded. Consider replacing relays related to ignition and engine management as a preventative measure, given the flood history.
- Inspect the Ignition Switch: Carefully inspect the ignition switch connector and wiring for corrosion or damage.
- Verify Ground Connections: Ensure all engine and chassis ground connections are clean and tight. Poor grounds can cause a multitude of electrical issues.
- Clear Codes and Re-scan: After inspecting and cleaning connections, attempt to clear the OBD2 codes again with a code reader. If they clear, drive the vehicle to see if they return. Monitor if the codes come back as “pending” or “permanent.”
- Professional Diagnosis: If the codes persist after these initial steps, it’s advisable to seek professional diagnosis from a qualified mechanic. They have specialized tools and expertise to further pinpoint electrical faults, test circuits, and potentially diagnose ECM/PCM issues if necessary.
While the initial repairs got the 2015 Chevy Traverse running, these OBD2 codes are crucial indicators of underlying electrical problems stemming from the flood damage. Systematic troubleshooting, focusing on wiring, connectors, fuses, and relays, is the most logical approach. Addressing these issues will not only clear the check engine light but also ensure the long-term reliability of the vehicle’s electrical system.
