Contour Enthusiasts Group Archives Forums General Troubleshooting O2 Sensor Code

I posted earlier about my O2 sensor causing the check engine light to come on, and looking at the Haynes manual and other CEGer's advice it looks like something I can do this weekend. Anyways when looking at the code list I see next to my code: P0153-Upstream Heated Oxygen Sensor circuit Slow Response - Bank No. 2. Does this mean that I only need to replace one of the O2 sensors? If so which one is it the front or the back? Any help would be greatly appreciated. TIA.

Do a search for O2 sensor or your code, there are tons of posts on O2's.

Can anyone else help me?

Originally posted by COntour:

---

Anyways when looking at the code list I see next to my code: P0153-Upstream Heated Oxygen Sensor circuit Slow Response - Bank No. 2. Does this mean that I only need to replace one of the O2 sensors?

---

Yes, the code points to one of the four O2 sensors (HO2S21 = Bank 2 Upstream) on your car.

Originally posted by COntour:

---

If so which one is it the front or the back?

---

Bank 1 is next to the firewall, Bank 2 is next to the radiator. The upstream sensor is next to the oil filter.

If the new O2 doesn't fix the problem (after you have reset the CEL), then the other possible causes (from the Ford TSP) are as follows:

-- Contaminated HO2S.
-- Exhaust leaks.
-- Shorted/open wires.
-- Excessive fueling.
-- MAF meter.
-- Air leaks.