P1202: (Alternative Fuel) Gas Mass Sensor Circuit Low Frequency

CADILLAC CHEVY CHRYSLER BUICK VOLKSWAGEN GM GMC OLDSMOBILE

Severity

Medium

System

Manufacturer-Specific Powertrain

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 P1202 Mean?

P1202 is a manufacturer-specific diagnostic trouble code: (Alternative Fuel) Gas Mass Sensor Circuit Low Frequency. This code applies to CADILLAC, CHEVY, CHRYSLER, BUICK, VOLKSWAGEN vehicles. Unlike generic OBD-II codes, manufacturer-specific codes are defined by the vehicle maker and may only apply to certain makes and models.

Symptoms of P1202

⚠️ Check Engine Light (MIL) illuminated
⚠️ (Alternative Fuel) Gas Mass Sensor reading at zero or minimum value
⚠️ Related system not functioning or in fail-safe mode
⚠️ Reduced engine performance

Common Causes

🔍 Open or broken wire in (Alternative Fuel) Gas Mass Sensor circuit
🔍 Poor ground connection at (Alternative Fuel) Gas Mass Sensor
🔍 Faulty (Alternative Fuel) Gas Mass Sensor with no output signal
🔍 Disconnected or loose (Alternative Fuel) Gas Mass Sensor connector
🔍 Blown fuse in related circuit

Frequently Asked Questions

What does P1202 mean?

P1202 indicates: (Alternative Fuel) Gas Mass Sensor Circuit Low Frequency. The vehicle's computer has detected that the (Alternative Fuel) Gas Mass Sensor is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P1202?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P1202 for extended periods may cause additional problems.

How much does it cost to fix P1202?

Repair costs for P1202 typically range from $20 to $300, 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

🔧 Repair broken wire or restore ground in (Alternative Fuel) Gas Mass Sensor circuit
🔧 Clean and secure (Alternative Fuel) Gas Mass Sensor connector and ground points
🔧 Replace failed (Alternative Fuel) Gas Mass Sensor

1
Find your vehicle above
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2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.