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2018 CADILLAC XT5

3.6L V6FWDAUTOMATICgas
Repairs0Labor479Torque3847Fluid6DTC969Battery0Maintenance0Recalls0
P1154moderate severityPowertrain

HO2S Transition Time Ratio Bank 2 Sensor 1

on 2018 Cadillac XT5 3.6L V6 · FWD

What this code means

The PCM detected an abnormal transition time ratio for the upstream O2 sensor on Bank 2. The sensor is transitioning faster in one direction than the other.

Symptoms

  • Check Engine Light
  • Poor fuel economy
  • Failed emissions test
  • Subtle performance loss

Common causes

  • Degraded O2 sensor Bank 2
  • Exhaust leak near sensor
  • Fuel system imbalance
  • Contaminated sensor

Diagnostic steps

  1. Monitor O2 sensor waveform
  2. Check for exhaust leaks
  3. Test fuel trim values
  4. Inspect sensor for contamination

Repair notes

Replace upstream O2 sensor Bank 2. Often appears with P1153.

Other Powertrain codes on this vehicle

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