C1138 Code: Meaning, Symptoms, Causes & Fix

Overview

Symptoms

• reduced stability control performance
• chassis warning indicator
• ABS/traction light on

Common causes

• Component failure in the monitored system affecting gear select position short to battery
• Control module logic or calibration issue
• Connector pin damage/corrosion or harness stress near related components

How to diagnose C1138

1. Confirm C1138 and capture freeze-frame data with a professional scan tool.
2. Inspect wiring, connectors, and grounds related to gear select position short to battery for obvious defects.
3. Use freeze-frame and live data to isolate whether the issue is electrical, mechanical, or control logic.
4. Check for related DTCs to identify the root-cause chain before replacing parts.
5. After repair, clear codes and confirm readiness monitors complete without recurrence.

Severity of code C1138

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

Can you drive with C1138?

The vehicle is often drivable with C1138, 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)

1. Repair obvious wiring/connector faults first to prevent repeat parts replacement.
2. Address the root fault mode (generic) in the gear select position short to battery circuit/system.
3. Apply the required relearn/adaptation procedure if specified by service information.
4. Road-test and verify C1138 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

$120-$500

Common mistakes when diagnosing C1138

• 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.

C1138 in common vehicles

C1138 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 C1138?

C1138 is commonly set by generic faults affecting gear select position short to battery.

How much does it cost to fix C1138?

For C1138, repair costs are typically $120-$500 depending on exact root cause, labor rates, and part quality.

Can I clear C1138 without repair?

You can clear C1138 temporarily, but the code usually returns until the underlying fault is corrected.

Helpful tools

• Estimate repair cost
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