P0602 Code: Meaning, Symptoms, Causes & Fix

Overview

P0602 is triggered when monitoring logic identifies an issue with Control Module Programming Error affecting module-to-module CAN communication.

Symptoms

intermittent no-start or limp mode
module not responding in scan tool
feature communication timeout

Common causes

Electrical fault in the affected circuit affecting control module programming error
Component failure in the monitored system
Connector pin damage/corrosion or harness stress near related components

How to diagnose P0602

Confirm P0602 and capture freeze-frame data with a professional scan tool.
Inspect wiring, connectors, and grounds related to control module programming error for obvious defects.
Use freeze-frame and live data to isolate whether the issue is electrical, mechanical, or control logic.
Check for related DTCs to identify the root-cause chain before replacing parts.
After repair, clear codes and confirm readiness monitors complete without recurrence.

Severity of code P0602

Low: This code is low to moderate severity in most cases, but diagnosis is still recommended to avoid recurring warnings.

Can you drive with P0602?

The vehicle is often drivable with P0602, but plan a repair window to prevent repeat faults.

If the warning lamp is flashing or drivability/safety is affected, avoid driving and diagnose immediately.

How to fix it (step-by-step)

Repair obvious wiring/connector faults first to prevent repeat parts replacement.
Address the root fault mode (generic) in the control module programming error circuit/system.
Apply the required relearn/adaptation procedure if specified by service information.
Road-test and verify P0602 remains cleared under the conditions that originally set the code.

Fix options

Clear code and confirm through drive cycle.
Inspect circuit and connector condition.
Clear DTCs and verify with live data and completed drive cycle.

Typical repair cost

$160-$600

Common mistakes when diagnosing P0602

Replacing parts without verifying voltage, ground, and signal integrity first.
Ignoring related stored/pending codes that indicate upstream faults.
Skipping post-repair verification drive cycle and readiness checks.

P0602 in common vehicles

P0602 appears across makes such as Mazda, Subaru, Lexus, Jeep. Failure patterns differ by platform: wiring routes, software calibration, and component supplier revisions can change root cause.

Frequently asked questions

What causes P0602?

P0602 is commonly set by generic faults affecting control module programming error.

How much does it cost to fix P0602?

For P0602, repair costs are typically $160-$600 depending on exact root cause, labor rates, and part quality.

Can I clear P0602 without repair?

You can clear P0602 temporarily, but the code usually returns until the underlying fault is corrected.