AutoCodes – Cadillac – B0978 Cadillac

B0978 Cadillac Code - Accessory Indicator Control Circuit

Quick Answer

The Ignition Mode Switch has 3 LEDs that indicate the vehicle power mode. Common causes include Faulty Ignition Mode Switch, Ignition Mode Switch harness is open or shorted, Ignition Mode Switch circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B0978 Cadillac indicates Accessory Indicator Control Circuit.
Common causes: Common causes include Faulty Ignition Mode Switch, Ignition Mode Switch harness is open or shorted, Ignition Mode Switch circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 853

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 11, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B0978 Cadillac Description

The Ignition Mode Switch has 3 LEDs that indicate the vehicle power mode. When the vehicle is in the Off mode, the Off LED may illuminate. Pressing the lower button of the ignition mode switch, the vehicle enters the accessory mode and ACC LED will illuminate. Keeping the lower button pressed for about 5-6 seconds, the vehicle enters run mode with the engine off and the START LED will illuminate. All these LEDs have the voltage supplied from the Body Control Module (BCM) through the ignition mode switch supply voltage circuit. The ground path for each LED is controlled by the BCM.

OBDII Code B0978 Cadillac - Accessory Indicator Control Circuit - AutoCodes.com — B0978 Cadillac Code - Accessory Indicator Control Circuit

What does this mean?

What are the Possible Causes of the DTC B0978 Cadillac?

Faulty Ignition Mode Switch
Ignition Mode Switch harness is open or shorted
Ignition Mode Switch circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B0978 Cadillac?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B0978 Cadillac code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B0978 Cadillac Code

1. What are the common symptoms of OBDII code B0978 Cadillac (Accessory Indicator Control Circuit)?

The common symptoms include the accessory indicator light not functioning properly, flickering, or staying on constantly.

2. What are the possible causes of OBDII code B0978 Cadillac?

Possible causes of this code include a faulty accessory indicator control circuit, a malfunctioning indicator control switch, or wiring issues.

3. How can I diagnose OBDII code B0978 Cadillac?

To diagnose this code, you can start by checking the accessory indicator control circuit for any visible damage or loose connections. Using a multimeter to test the circuit's voltage and continuity may also help pinpoint the issue.

4. What repair tips can help fix OBDII code B0978 Cadillac?

Repair tips include inspecting and repairing any damaged wiring, replacing a faulty indicator control switch, and resetting the OBDII trouble code after making repairs.

5. Can OBDII code B0978 Cadillac cause any other problems in the vehicle?

While this code is related to the accessory indicator control circuit, it may not directly cause any significant performance issues in the vehicle. However, it's still important to address the underlying problem to ensure all systems are functioning properly.

6. Is it safe to continue driving with OBDII code B0978 Cadillac present?

In most cases, it should be safe to continue driving with this code, as it primarily affects the accessory indicator light. However, it's recommended to address the issue promptly to prevent any potential electrical problems down the line.

7. How much does it typically cost to repair OBDII code B0978 Cadillac?

The cost of repairing this code can vary depending on the underlying cause. Repair costs may range from a simple fix like replacing a switch or repairing wiring to a more complex issue that requires professional diagnostics and labor.

8. Can I reset OBDII code B0978 Cadillac without fixing the underlying issue?

While you can reset the trouble code using an OBDII scanner, it's important to address the root cause of the problem to prevent the code from reappearing. Simply resetting the code without fixing the issue will not solve the underlying problem.

9. How long does it take to repair OBDII code B0978 Cadillac?

The repair time for this code can vary based on the cause of the issue. Simple fixes like replacing a switch may take a short amount of time, while more complex wiring issues may require additional diagnostic time and labor.

10. Are there any recalls or technical service bulletins related to OBDII code B0978 Cadillac?

It's recommended to check with Cadillac dealerships or online resources for any recalls or technical service bulletins related to this OBDII code. Manufacturers may provide guidance or assistance for known issues associated with this code.