AutoCodes – Cadillac – P1650 Cadillac

P1650 Cadillac Code - PCM Output Controls Fault

Quick Answer

The Quad Driver Module (QDM) is an electronic switch that completes a ground circuit when switched on. Common causes include Faulty Powertrain Control Module (PCM), Powertrain Control Module harness is open or shorted, Powertrain Control Module 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: P1650 Cadillac indicates PCM Output Controls Fault.
Common causes: Common causes include Faulty Powertrain Control Module (PCM), Powertrain Control Module harness is open or shorted, Powertrain Control Module 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 4,911

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 Jan 12, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1650 Cadillac Description

The Quad Driver Module (QDM) is an electronic switch that completes a ground circuit when switched on. The QDM independently controls 4 separate outputs. A load is connected between battery voltage and the QDM allowing QDM driver to control the output. Each QDM has a fault detection logic that compares its input and output voltages. The logic expects to measure less than 3 volts when the QDM is on and greater than 7 volts when off. The QDM has only one fault that will detect a fault on any of the 4 outputs. The scan tool can be used to cycle the outputs on and off. It can also perform automated test which can isolate the faulty circuit.
The Diagnostic Trouble Code (DTC) P1650 and P1651 will set if there is an open, short to ground or short to voltage on any of the QDM output circuits, faulty MIL circuit, faulty upshift light circuit, faulty cooling fan relay circuit or A/C relay circuit. Fault detected for 5 seconds will set P1651. Fault detected for 20 seconds will set P1650. The QDM circuit is continuously checked when the engine is running.
The Quad Driver Module (QDM) is part of the Powertrain Control Module (PCM).

OBDII Code P1650 Cadillac - PCM Output Controls Fault - AutoCodes.com — P1650 Cadillac Code - PCM Output Controls Fault

What does this mean?

What are the Possible Causes of the DTC P1650 Cadillac?

Faulty Powertrain Control Module (PCM)
Powertrain Control Module harness is open or shorted
Powertrain Control Module circuit poor electrical connection

How to Fix the DTC P1650 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 P1650 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 P1650 Cadillac Code

1. What does the OBDII code P1650 mean on a Cadillac?

P1650 on a Cadillac indicates a "PCM Output Controls Fault," meaning the Powertrain Control Module (PCM) has detected an issue with one or more output control circuits.

2. What are the common symptoms of the P1650 code?

Symptoms may include the check engine light turning on, poor engine performance, issues with accessories like fans or lights, and possibly transmission shifting problems.

3. What causes the P1650 code to appear on a Cadillac?

Common causes include faulty wiring or connectors, a malfunctioning PCM, a short circuit, or issues with related components like relays or sensors.

4. Can a faulty PCM cause the P1650 code?

Yes, a damaged or failing PCM can cause the P1650 code by failing to properly control output circuits.

5. How do I diagnose the P1650 code on my Cadillac?

Start by visually inspecting the wiring and connectors for damage or corrosion, then use a multimeter to test for continuity and proper voltage in the affected circuits. A scan tool can also help identify specific output components causing the issue.

6. Is the P1650 code serious?

While it may not immediately affect drivability, ignoring this code can lead to performance issues or damage to other components, so it should be addressed promptly.

7. Can I drive my Cadillac with the P1650 code active?

It’s possible to drive with this code, but it’s not recommended, as it may lead to further damage or unexpected failures.

8. How do I fix the P1650 code on a Cadillac?

Repairs may include replacing damaged wiring, cleaning or reconnecting corroded connectors, replacing faulty relays or sensors, or reprogramming or replacing the PCM if necessary.

9. How much does it cost to fix the P1650 code?

Repair costs can vary widely, from under $100 for simple wiring repairs to over $1,000 if the PCM needs replacement or reprogramming.

10. Can the P1650 code clear itself after repairs?

In some cases, the code may clear after fixing the underlying issue, but it’s usually recommended to use a scan tool to clear the code manually and verify the repair.