P1651 Pontiac 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
- P1651 Pontiac 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.
Code P1651 Pontiac Description
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).
What are the Possible Causes of the DTC P1651 Pontiac?
- 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 P1651 Pontiac?
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 P1651 Pontiac 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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Frequently Asked Questions about P1651 Pontiac Code
1. What does the P1651 code mean on a Pontiac?
P1651 indicates a "PCM Output Controls Fault," which means the Powertrain Control Module (PCM) has detected an issue with one of its output control circuits.
2. What are the common symptoms of a P1651 code in a Pontiac?
Common symptoms include the check engine light turning on, cooling fan or A/C system malfunctions, and possible engine overheating.
3. What causes the P1651 code to appear?
The code can be caused by a faulty cooling fan relay, damaged wiring or connectors in the output control circuit, or a malfunctioning PCM.
4. Can a bad cooling fan relay trigger the P1651 code?
Yes, a faulty cooling fan relay is one of the most common reasons for the P1651 code, as the PCM relies on it for proper cooling fan operation.
5. How do I diagnose the P1651 code on my Pontiac?
Start by inspecting the cooling fan relay, wiring, and connectors for damage or corrosion. Use a multimeter to test for continuity and proper voltage in the circuits.
6. Can a failing PCM cause the P1651 code?
Yes, but it is less common. The PCM itself may be faulty if all other components and wiring are in good condition.
7. Is it safe to drive with a P1651 code?
Driving with this code can be risky, especially if it leads to cooling fan failure and potential engine overheating. Address the issue promptly.
8. How do I fix the P1651 code on a Pontiac?
Repairs may include replacing a faulty cooling fan relay, repairing damaged wiring or connectors, or, in rare cases, replacing the PCM.
9. Can I reset the P1651 code without fixing the issue?
You can clear the code using an OBDII scanner, but it will likely return if the underlying issue is not addressed.
10. What tools do I need to troubleshoot the P1651 code?
You'll need an OBDII scanner, a multimeter, and possibly wiring diagrams for your Pontiac to properly diagnose and repair the issue.
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