C0077: Low Tire Pressure (Subfault)

What it means

This code identifies a fault associated with low tire pressure. The specific failure depends on the diagnostic subtype.

At a glance

• Usually lights the ABS or stability-control warning light

How it works

The vehicle's tire-pressure monitoring system (TPMS) reports that one or more tires are below the pressure threshold it monitors. C0077 identifies a low-pressure condition subfault; it does not by itself identify which tire is low.

Common causes

Most likely first.

1. Tire(s) under-inflated

Symptoms

• Low tire pressure warning light

How to diagnose it

1. Read the C0077 subtype and TPMS data to see whether the vehicle reports a specific tire or pressure.
2. Measure all tire pressures when the tires are cold and compare them with the vehicle's door-jamb placard or owner's manual, not the tire sidewall maximum.
3. Look for a puncture, damaged valve, bead leak, or other visible cause on any tire that is low.
4. Inflate the tires to the vehicle's specified cold pressures and recheck them after a short interval for pressure loss.
5. If pressures are correct but the code returns, scan each TPMS sensor and inspect its valve-area sensor and the system for a sensor or signal fault.

Common fixes

• Inflate the under-pressured tire or tires to the vehicle's specified cold pressure.
• Repair a puncture when it is safely repairable, or replace a damaged tire.
• Replace a leaking valve or valve seal.
• Replace a failed TPMS sensor if pressure and sensor tests confirm it.

Can I keep driving?

Check and correct the pressures before driving far, since under-inflation can overheat and damage a tire and reduce handling. If a tire is visibly damaged or loses pressure quickly, do not drive on it.