U0688: Lost Communication With Throttle Position Sensor/Switch G

Severity

Medium

System

Vehicle Systems

Last reviewed: Jan 1, 0001 Last updated: Jan 1, 0001

Methodology: We combine code standards with complaint and reliability patterns, then review for clear, vehicle-first diagnosis steps.

Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).

Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.

What Does U0688 Mean?

U0688 is a diagnostic trouble code indicating: Lost Communication With Throttle Position Sensor/Switch G. This code relates to the vehicle systems system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of U0688

⚠️ Check Engine Light (MIL) illuminated
⚠️ No communication with Throttle Position Sensor/Switch G
⚠️ Multiple warning lights may illuminate simultaneously
⚠️ Related system completely inoperative
⚠️ System warning light illuminated

Common Causes

🔍 CAN bus wiring fault (open or shorted) to Throttle Position Sensor/Switch G
🔍 Power or ground supply issue to Throttle Position Sensor/Switch G
🔍 Throttle Position Sensor/Switch G internal failure
🔍 Water intrusion damaging module or connectors
🔍 CAN bus termination resistor fault

Frequently Asked Questions

What does U0688 mean?

U0688 indicates: Lost Communication With Throttle Position Sensor/Switch G. The vehicle's computer has detected that the Throttle Position Sensor/Switch G is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code U0688?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with U0688 for extended periods may cause additional problems.

How much does it cost to fix U0688?

Repair costs for U0688 typically range from $80 to $800, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.

What To Do Next

Possible Fixes

🔧 Inspect CAN bus wiring to Throttle Position Sensor/Switch G for damage
🔧 Check power and ground supply to Throttle Position Sensor/Switch G
🔧 Replace failed Throttle Position Sensor/Switch G

1
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2
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3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.