AutoCodes – Cadillac – B0780 Cadillac

B0780 Cadillac Code - Four Wheel Drive Low Range Indicator Circuit

Quick Answer

The Four-Wheel Drive (4WD) Low Range (LO) indicator circuit consists of a Light Emitting Diode (LED) feed circuit, a LED, and a LED control circuit. Common causes include Faulty Transfer Case Select Switch, Transfer Case Select Switch harness is open or shorted, Transfer Case Select Switch circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: B0780 Cadillac indicates Four Wheel Drive Low Range Indicator Circuit.
Common causes: Common causes include Faulty Transfer Case Select Switch, Transfer Case Select Switch harness is open or shorted, Transfer Case Select Switch circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 864

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Nov 18, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B0780 Cadillac Description

The Four-Wheel Drive (4WD) Low Range (LO) indicator circuit consists of a Light Emitting Diode (LED) feed circuit, a LED, and a LED control circuit. The indicator dimming control circuit is the LED feed circuit and continuously supplies B+ to the 2WD HI, 4WD Auto, 4WD HI, and 4WD LO LEDs. When the 4WD LO mode has been selected by the driver, the Transfer Case Shift Control Module (TCCM) provides a ground through the 4WD LO indicator control circuit illuminating the LED.
The TCCM tests the 4WD LO indicator circuit for unexpected voltage by monitoring the B+ supplied by the Body Control Module (BCM) on the indicator dimming control circuit by grounding the 4WD LO indicator control circuit for 2 seconds during the Bulb Test at key ON.

OBDII Code B0780 Cadillac - Four Wheel Drive Low Range Indicator Circuit - AutoCodes.com — B0780 Cadillac Code - Four Wheel Drive Low Range Indicator Circuit

What does this mean?

What are the Possible Causes of the DTC B0780 Cadillac?

Faulty Transfer Case Select Switch
Transfer Case Select Switch harness is open or shorted
Transfer Case Select Switch circuit poor electrical connection
Faulty Transfer Case Shift Control Module (TCCM)

How to Fix the DTC B0780 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 B0780 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 B0780 Cadillac Code

1. What does the OBDII code B0780 mean for a Cadillac?

The code B0780 indicates a problem with the Four Wheel Drive Low Range Indicator Circuit, which is responsible for signaling the low-range mode status in the four-wheel-drive system.

2. What are the common symptoms of the B0780 code?

Symptoms may include the four-wheel-drive low-range indicator not illuminating, difficulty engaging low-range mode, or a service 4WD warning light on the dashboard.

3. What causes the B0780 code in a Cadillac?

Common causes include a faulty low-range indicator light, wiring issues such as corrosion or damage, a malfunctioning transfer case control module, or a problem with the four-wheel-drive switch.

4. Can I still drive my Cadillac with the B0780 code?

Yes, you can drive the vehicle, but the four-wheel-drive low-range functionality may not work as intended, which could impact performance in off-road or low-traction conditions.

5. How do I troubleshoot the B0780 code?

Start by inspecting the wiring and connectors for the low-range indicator circuit, checking for corrosion or damage. Test the indicator bulb or LED, and verify the operation of the transfer case control module and switch.

6. How is the B0780 code typically repaired?

Repairs may involve replacing a faulty indicator light, repairing or replacing damaged wiring, recalibrating or replacing the transfer case control module, or replacing a defective switch.

7. Can a faulty transfer case control module cause the B0780 code?

Yes, a malfunctioning transfer case control module can cause issues with the low-range indicator circuit and trigger the B0780 code.

8. Will clearing the B0780 code fix the problem?

Clearing the code may temporarily turn off the warning, but the underlying issue must be addressed to prevent the code from returning.

9. How much does it cost to fix the B0780 code on a Cadillac?

Repair costs can vary widely depending on the cause, ranging from $50 to $300 for minor wiring repairs, or more for component replacements like the transfer case control module.

10. Can a scan tool help diagnose the B0780 code?

Yes, a scan tool can help identify the code and monitor the operation of the four-wheel-drive system, making it easier to pinpoint the issue in the low-range indicator circuit.