C0290 – Lost Communications With PCM

System: Chassis | Standard: ISO/SAE Controlled | Fault type: General

Official meaning: Lost Communications With PCM

Definition source: SAE J2012 naming/structure guidance

What Does C0290 Mean?

C0290 – Lost Communications With PCM means exactly this: Lost Communications With PCM. A chassis-related control module has determined that it is no longer receiving the required communication from the PCM (Powertrain Control Module) over the vehicle communication network. This is a General fault under an ISO/SAE Controlled definition and is associated with the Chassis system.

C0290 identifies a loss of communication condition rather than proving a specific part has failed. The PCM may be fully functional but temporarily unavailable to other modules due to a power/ground interruption, a network wiring issue, or a connector/terminal problem. When the expected PCM messages are missing for a calibrated period, the chassis module stores C0290 to document that the communication link to the PCM was lost.

Quick Reference

• Code: C0290
• Official Title: C0290 – Lost Communications With PCM
• Official Meaning: Lost Communications With PCM
• Fault Type: General
• Standard classification: ISO/SAE Controlled
• System: Chassis
• What it indicates: A chassis module is not receiving expected PCM communications
• What it does not prove: That the PCM itself is necessarily defective

Symptoms

Symptoms depend on which chassis functions require PCM data and how the vehicle responds when communication is lost. Possible symptoms include:

• Warning indicators illuminated: chassis-related warning lights and/or messages may appear when the fault is detected
• System feature limitations: certain chassis functions may be reduced, unavailable, or placed into a fallback mode when PCM data is not available
• Intermittent behavior: symptoms may appear and disappear if communication is lost and then restored
• Multiple diagnostic trouble codes: other communication-related or module-status codes may be stored in one or more modules
• Scan tool access issues: some scan sessions may show intermittent inability to communicate with the PCM or other modules if the network is disrupted

Common Causes

C0290 is set when the expected PCM communications are not received. Common underlying causes include:

• PCM power supply interruption: a blown fuse, faulty relay, high resistance in a power feed, or an intermittent ignition feed can cause the PCM to drop offline
• PCM ground issue: loose, corroded, or high-resistance grounds can lead to resets or shutdowns that interrupt communication
• Connector or terminal problems: poor pin fit, corrosion, moisture intrusion, damaged seals, or partially latched connectors at the PCM or the reporting module
• Harness damage: chafed, pinched, stretched, or heat-damaged wiring affecting network circuits or module power/ground circuits
• Network circuit faults: opens, shorts to power, shorts to ground, or excessive resistance on the communication lines used for PCM messaging
• Low system voltage: a weak battery, poor battery connections, or charging system problems can cause module resets and communication dropouts
• Module internal fault or software issue: less likely than external electrical causes, but possible after power/ground and network integrity are confirmed

Diagnosis Steps

Diagnosing C0290 requires confirming whether the PCM is actually offline, whether the network is disrupted, or whether the reporting module is failing to receive specific messages. Use a scan tool capable of reading chassis codes and module status, a digital multimeter, and the correct wiring information for the exact vehicle configuration.

1. Perform a full system scan. Record all stored and pending DTCs in every module. Note which modules report communication problems and whether the PCM is listed as not communicating.
2. Review failure records/freeze-frame data (if available). Identify when the issue occurs (key-on, cranking, running, or intermittently).
3. Verify battery voltage and connection integrity. Inspect battery terminals for looseness and corrosion. Confirm stable system voltage with the key on and during cranking if applicable.
4. Check PCM power feeds. Identify PCM fuses and relays that supply battery and ignition power. Confirm voltage is present at the supply points and remains present under load (not just a visual fuse check).
5. Check PCM grounds with a voltage drop test. With electrical loads applied (and during cranking where appropriate), measure voltage drop across ground paths to find high resistance that can cause resets and communication loss.
6. Inspect the PCM connector(s) and the connector of the module that set C0290. Look for moisture intrusion, corrosion, bent pins, pushed-out terminals, damaged locks, and damaged seals. Ensure connectors are fully seated and locked.
7. Confirm scan tool communication behavior. Determine whether PCM communication is consistently unavailable or intermittent. If intermittent, observe whether it changes with key cycling or harness movement.
8. Inspect and test network wiring using the wiring diagram. With the vehicle powered down and following safe procedures, check the relevant communication circuits for opens, shorts, and abnormal resistance. Inspect splice points and areas where the harness may be stressed.
9. Wiggle test with monitoring (when safe). While monitoring module communication status or related parameters, gently manipulate suspect harness sections and connectors to identify an intermittent open or poor connection.
10. Only after external causes are ruled out, evaluate module-related causes. If power, ground, connectors, and network wiring test correctly, consider whether a module software update, configuration issue, or internal module fault is responsible. Module replacement (if required) may involve setup or programming.

Possible Fixes

• Repair or restore PCM power supply circuits (replace failed fuse/relay, repair open/high-resistance power feed)
• Repair PCM ground circuits (clean/tighten ground points, repair damaged ground wires/straps, correct high-resistance connections)
• Repair or replace damaged terminals, seals, or connectors at the PCM or the module that reported C0290
• Repair harness damage affecting communication lines or module power/ground circuits (chafing, pinched wiring, poor splices)
• Correct network circuit faults (repair opens/shorts, address abnormal resistance, restore proper circuit integrity)
• Correct low-voltage conditions (service battery connections, address charging system problems if present)
• Update or reconfigure control module software where applicable after electrical integrity is verified

Can I Still Drive With C0290?

C0290 indicates that a chassis module has lost communication with the PCM. Whether the vehicle can be driven safely depends on what functions are affected when PCM data is unavailable. If the vehicle displays warning indicators or reduces chassis-related functionality, driving conditions may change and certain features may not operate as intended.

If you notice altered vehicle behavior, multiple warning indicators, or intermittent electrical/network issues, minimize driving and prioritize diagnosis. Because this code relates to chassis system communication, it should be treated as potentially safety-relevant until the root cause is confirmed and corrected.

Repair Costs

Repair cost depends on whether the confirmed root cause is wiring, connector condition, a switch or module issue, or the labor needed to diagnose the fault correctly.

Last updated: March 25, 2026