Powertrain, generic (extended)

P2489 Exhaust Gas Temperature Sensor Circuit Intermittent/Erratic (Bank 2 Sensor 5)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2489 points to an unsteady signal from the fifth exhaust probe on bank 2: the value stays within its electrical limits but jumps or drops out briefly. This code is not documented by any manufacturer, as no public layout carries five probes per bank on a twin-bank engine. For the bank 1 position GM shows the method under P2484: samples every 100 ms are compared, and in 2025 a step above 100 °C in 12 of 25 samples, valid only between 140 and 1070 °C, sets a Type B fault. CARB requires monitoring of inputs for erratic behaviour where it affects emissions. Such faults usually come from loose terminals or a harness that touches hot parts, so a careful check of routing and clips pays off.

Likely causes

Loose terminal in the connector
Harness touching hot exhaust parts
Internal crack in the probe

Symptoms

  • Warning lamp coming and going
  • Jumping value in live data

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–350
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

egt sensor b2s5

Related codes

P2484P2485P2486P2487P2488

References: law.cornell.edu, gsi.ext.gm.com.