Computer keeps throwing different codes. | Ford Escort Owners Association (FEOA)

Computer keeps throwing different codes.

Discussion in '3rd Gen 1997-2002 2.0L SOHC' started by Gamer92, Nov 25, 2012.

  1. Gamer92

    Gamer92 FEOA Donator

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    Hello,

    I have a 98' tracer and recently it started to throw a p1131 code. I unhooked battery with car off and the code was reset, after 30 minutes a new code was thrown, P0136. I had this code in August and replaced the downstream o2 sensor. Haven't seen code until now. So, basically the computer is picking up p0420, p1131, and p0136. The codes do not appear at the same time. I have checked all vacuum lines, fuel injectors are squirting, new plugs and wires, new air filter, cleaned MAF. So I'm thinking the P1131 may be a bad b1s1 sensor since it has about 20,000 miles on it. Car runs fine and gas milage seems to be fine. Thanks for any help
  2. FordMan59

    FordMan59 FEOA Member

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    P1131 is a bank 1 sensor 1 code often set when you have a bad upstream 02 sensor. P0136 is a bank 1 sensor 2 code and P0420 is a catalyst inefficiency code. Sounds like the upstream and downstream 02 sensors are relaying bad readings to the ECU. All three codes could be the result of bad 02 sensors. That's where I'd begin.
  3. Gamer92

    Gamer92 FEOA Donator

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    The downstream O2 is brand new with less than 5000 miles. It was replaced in late August but it is a Bosch and I've read bad things about their O2 sensors, so maybe it failed prematurely.
  4. FordMan59

    FordMan59 FEOA Member

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    If the upstream sensor only had 20K and downstream sensor only 5K miles on them neither should be bad unless you just got bad sensors. Most higher quality brand sensors will last ~100K. Maybe it's something in the 02 sensor wiring circuit?? I've never used Bosch sensors in the downstream position, but I've used them in the upstream position and had them last well over 100K miles.
  5. Gamer92

    Gamer92 FEOA Donator

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    What brand of sensors do you use? The only ones I have seen around here are Bosch and Denso.
  6. madmatt2024

    madmatt2024 FEOA Member

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    I used a Denso sensor when my OEM downstream sensor went, no issues. The OEM sensor is an NTK/NGK sensor.
  7. Intuit

    Intuit FEOA Member

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    Not many people have the code charts memorized. So it might help you to help them by saving them the time of looking up the codes on the chart.

    http://repairpal.com/obd-II-code-chart
    P0420 Catalyst System Efficiency Below Threshold (Bank #1)
    P1131 n/a
    P0136 O2 Sensor Circuit Malfunction (Bank #1 Sensor #2)

    Check to see whether your O2 sensor is still within manufacturer warranty period. The parts store should have your warranty information retrievable by phone number.
  8. madmatt2024

    madmatt2024 FEOA Member

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    P1131 FORD - Lack of Upstream Heated Oxygen Sensor Switch Sensor Indicates Lean Bank 1
  9. FordMan59

    FordMan59 FEOA Member

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    Thank you Matt. I knew what the code was, I had it just a few months ago on the '02, a new upstream 02 sensor took care of the problem. Usually for upstream sensors I use Bosch. I've never had to replace but one downstream sensor and it was several years ago on my '96 Contour, I don't remember the brand I used, but may have been Standard or NTK. I know it wasn't a Bosch.
  10. Intuit

    Intuit FEOA Member

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    Should've refreshed the page before posting. Had walked-off for several hours before coming back to it.
  11. TripleLude

    TripleLude FEOA Member

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    I think all the 10% ethanol gas causes problems with older-design O2 sensors, catalytic converters, fuel pumps, and other related stuff. In my ddd/race car, I use Shell or BP Premium. Shell premium is the only gas in my area that does not contain ethanol.

    I've had to replace O2 sensors on several cars in the past 6 months, which is strange. I think it is in the fuel.
  12. white-lightning

    white-lightning FEOA Member

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    From my 1996 owners manual:

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