P0688 Audi Code - Electronic Control Module Power Relay Control Circuit Open
Quick Answer
The Engine Control Module (ECM) monitors the power inputs. Common causes include Weak battery, Low voltage while cranking, Faulty Engine Control Module (ECM) relay. 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
- P0688 Audi indicates Electronic Control Module Power Relay Control Circuit Open.
- Common causes
- Common causes include Weak battery, Low voltage while cranking, Faulty Engine Control Module (ECM) relay.
- 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 P0688 Audi Description
What are the Possible Causes of the DTC P0688 Audi?
- Weak battery
- Low voltage while cranking
- Faulty Engine Control Module (ECM) relay
- Blown ECM fuse
- Faulty ECM
- ECM harness is open or shorted
- ECM circuit poor electrical connection
How to Fix the DTC P0688 Audi?
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.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0688 Audi 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 P0688 Audi Code
1. What does OBDII code P0688 mean on an Audi?
P0688 indicates an "Electronic Control Module Power Relay Control Circuit Open," meaning an issue with the relay or its circuit that supplies power to the ECM.
2. What are the symptoms of code P0688 in an Audi?
Common symptoms include the engine not starting, stalling while driving, no communication with the ECM, and possibly other warning lights on the dashboard.
3. What causes the P0688 code to appear in an Audi?
Possible causes include a faulty ECM power relay, damaged wiring or connectors, a blown fuse, or a defective ECM.
4. Can a faulty ECM power relay cause the P0688 code?
Yes, a malfunctioning ECM power relay is one of the most common causes of this code.
5. How do I diagnose code P0688 on my Audi?
Start by checking the ECM power relay, fuses, and related wiring for damage or loose connections. Use a multimeter to test for proper voltage and continuity.
6. Can a blown fuse trigger the P0688 code?
Yes, a blown fuse in the ECM power circuit can disrupt power delivery and cause this code.
7. Is it safe to drive an Audi with the P0688 code?
Driving with this code is not recommended, as it can lead to stalling or prevent the engine from starting altogether.
8. How do I fix code P0688 on an Audi?
Repairs may involve replacing the ECM power relay, fixing or replacing damaged wiring, replacing a blown fuse, or in rare cases, repairing or replacing the ECM.
9. What tools are needed to troubleshoot P0688?
You'll need a diagnostic scanner, a multimeter for electrical testing, and possibly a wiring diagram for your specific Audi model.
10. Can a bad ECM cause the P0688 code?
While rare, a faulty ECM can cause this code if internal failures prevent the circuit from functioning properly.
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