AutoCodes – Cadillac – B0977 Cadillac

B0977 Cadillac Code - Start 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: B0977 Cadillac indicates Start 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 800

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 B0977 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 B0977 Cadillac - Start Indicator Control Circuit - AutoCodes.com — B0977 Cadillac Code - Start Indicator Control Circuit

What does this mean?

What are the Possible Causes of the DTC B0977 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 B0977 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 B0977 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 B0977 Cadillac Code

1. What does the OBDII code B0977 mean on a Cadillac?

The B0977 code indicates a problem with the Start Indicator Control Circuit, which may involve a malfunction in the electrical circuit responsible for signaling the start process.

2. What are the common symptoms of code B0977 in a Cadillac?

Symptoms may include the vehicle not starting, the start indicator light not illuminating, or intermittent issues with the ignition system.

3. What causes the B0977 code to appear?

Common causes include a faulty start indicator bulb, damaged wiring or connectors in the start circuit, or a malfunctioning ignition switch.

4. Can a blown fuse trigger the B0977 code?

Yes, a blown fuse in the start indicator circuit can disrupt the electrical flow and trigger this code.

5. How do I diagnose the B0977 code on my Cadillac?

Use a diagnostic scanner to confirm the code, inspect the start indicator bulb, check connectors and wiring for damage, and test the ignition switch for proper function.

6. Can a bad battery cause the B0977 code?

A low or failing battery can potentially cause electrical issues, but it is not a direct cause of the B0977 code. Ensure the battery is fully charged before further diagnosis.

7. Is it safe to drive with the B0977 code active?

It may not be safe, as this code can indicate issues with the starting system. Driving could result in the vehicle failing to start in the future.

8. How much does it cost to fix the B0977 code on a Cadillac?

Repair costs vary depending on the issue, but fixing damaged wiring or replacing a faulty indicator bulb typically costs between $50 and $200.

9. Can I clear the B0977 code without repairs?

You can clear the code with a diagnostic scanner, but if the underlying issue isnâ€™t resolved, the code will likely return.

10. Do I need a mechanic to fix the B0977 code?

If youâ€™re comfortable inspecting electrical components and using a multimeter, you can attempt repairs yourself. Otherwise, itâ€™s best to have a professional handle the issue.