Powertrain, generic · Fuel and air metering

P013C O2 Sensor Slow Response - Rich to Lean Bank 2 Sensor 2

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

The downstream oxygen sensor (sensor 2, after the catalytic converter) is used for fine mixture trim and to monitor the converter. 'Slow response' means the signal transition itself is too sluggish – it takes too long to pass between two voltage levels. This code covers the rich-to-lean direction, usually tested during deceleration fuel cut-off. Bank 2 only exists on V and boxer engines. GM forces the test itself and measures how quickly the signal passes from 450 to 150 mV relative to air flow; a filtered value above its limit sets the code after one trip (fallback: target not reached before about 70 g of air). Ford reports the same slew-rate test for bank 2 under this code. CARB requires separate detection of slow and delayed faults in each direction (phased in from 2009 for downstream and 2011 for upstream sensors).

Likely causes

Downstream oxygen sensor aged or contaminated (soot, oil, silicone, coolant)
Exhaust leak between manifold/turbo and the sensor
Converter faulty or non-original with different oxygen storage
Control module software too sensitive (update available)
Sensor connector or wiring with contact resistance

Symptoms

  • Check engine light on
  • Usually no noticeable change in driving
  • Catalyst monitor may stay incomplete (inspection readiness missing)
  • With a converter cause, P0420/P0430 may follow

Repair estimate

DifficultyEasyDIY possible
Parts and labour€60–250
Time0.5–1.5 h

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

Parts involved

oxygen sensor bank2 sensor2exhaust systemcatalytic converter

Related codes

P013DP014AP013AP0159P2272P0430

References: law.cornell.edu, gsi.ext.gm.com, newtonnet.co.uk.