Dakota Code

Asked by Jan 01, 2017 at 09:52 AM

Question type: Maintenance & Repair

I have a 02 dakota 3.9 an I'm getting code p0138
bank 1 sensor 2 ..when using scanner to see live
data what do I need too look for on those diagrams
showing 02 activity/readings to know which is
bad?..Theres a wave pattern an a digital screen..
Can issue with coolant tempt sensor signal cause
this also?
Any info is appreciated.
Thanks

1 Answer

73,735

P0138 DODGE - O2 sensor 1/2 Circuit high - Possible causes are - Faulty Rear Heated Oxygen Sensor Bank 1 - Rear Heated Oxygen Sensor Bank 1 harness is open or shorted - Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection - Intake air leaks - Exhaust gas leaks - Inappropriate fuel pressure - Faulty fuel injectors........The Heated Oxygen Sensor 2 (HO2S) (Rear O2 Sensor), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. For optimum catalyst operation, the air fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. The HO2S output voltage changes suddenly in the vicinity of the stoichiometric ratio. The Engine Control Module (ECM) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The HO2S generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxygen in the exhaust gas increases, the air-fuel ratio becomes Lean. The ECM interprets Lean when the HO2S voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The ECM interprets Rich when the HO2S voltage is above 0.45 V. -- Hope this helps...

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