Question about Jaguar XJS

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The car failed Emissions test. It was discovered the Oxygen Sensor Circuit - DTC 44 (code) was defective. When the ECM was replaced, the car passed Emissions testing. I drove the car home and then to work the next day which was a total of 14 miles. When I was ready to turn the car off, the check engine light came back on. I brought the car back and the ECM had to be replace again. Once again, home and to work (14 miles) and the check engine light came back on. The ECM has to be replace again. My question is before we start guessing and replacing expensive parts in hopes of finding the problem, what would cause the ECM to go out continually?

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  • thedude45 Oct 01, 2009

    the car is a 1994 and his readouts go to 93'. The engine runs smoothly at all times even with the check engine light on. The feedback voltage is between 1 and 4 volts. The code 44 is the same everytime.

  • thedude45 Oct 01, 2009

    the volts are 1-4. the car runs very smoothly all the time and it is a 1994

  • thedude45 Oct 01, 2009

    Thank you for your suggestions. I will let the mechanic at the garage know.

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  • 333 Answers

The ECM is not going out continually, the shop is diagnosing the problem wrong and putting an ECM in it when it has not failed. The code 44 is a two trip logic code, meaning it needs two 'official' drive cycles before it triggers the light. This is why you are getting 14 miles or so before it recurs. I presume it is the same code each time as well. ECMs are almost never the cause of this code, and furthermore, ECM failures almost always render this vehicle either inoperable or extremely erratic. Based on the code being a pre-OBD2 code, technical information is based on early 90s XJSs. If this is a later model let me know and I will give you the newer technical specifications for voltages. The majority of the time your Oxygen sensor has failed. Unfortunately there is no home-test that can be done to reliably. The vehicle needs to be hooked to a scantool that can display a data list of sensor outputs. The Oxygen sensor needs to have a flutuating voltage ranging from ~1v to 5v, alternating every half second. An analog multimeter can sometimes pick this up, but not always reliably enough to condemn a part, particularly on newer systems. If the signal is good, which it likely is not, the next step is to verify the heater element is intact on the sensor. This can be done by either checking resistance across the heater wires or verifying voltage on ground side of heater. Other far less likely causes are damage to wiring, or sticking/stuck injectors (this would cause a drivability concern as well, which you do not describe so is likely out).

Posted on Oct 01, 2009

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  • Superbovine Oct 01, 2009

    I apologize for the paragraph; it was spaced out nice and clearly when I typed it!

    If you have any follow up questions or need clarification, let me know :)


  • Superbovine Oct 01, 2009

    Thanks, I suspected 93 or 94.

    If the reading is a steady fluctuation 1 to 4v, it sounds like a solid reading. This verifies several things; number one that all your wiring for sensor values is OK. Two, your ECM is OK, as it is providing the 5V reference signal to the sensor, and it is recording a valid O2 signal returning.

    Next step would be to verify the heater circuit is good. You can do this by unhooking the sensor and testing resistance across the 5V reference wire and the heater ground wire. Any reading short of infinite resistance will be acceptable.

    If this is OK, things are going to get hairy fast. The remaining causes will all be standalone issues that are resulting in the O2 sensor giving values that make it appear to be malfunctioning.... again this is a longshot as 1) you have no drivability issues, and 2) your sensor outputs appear to be valid.

    Regardless, the next step would be to check your fuel pressure, as low pressure could result in leaner than normal O2 outputs at higher engine loads.
    My money is still on a failed O2 sensor though. The consistency of your code recurring makes it more likely to be a physical fault (burnt open heater element), as it would require nothing of you to reproduce the problem, other than running the car for two drive cycles.




  • Superbovine Oct 01, 2009

    And just to clarify, the voltage being "1 to 4 volts", this is a fluctuating reading, correct?
    You should be able to monitor something like this:

    ~1v 0.0seconds
    ~4v 0.5seconds

    ~1v 1.0seconds
    ~4v 1.5seconds

    ~1v 2.0seconds
    Et cetera

    If it is just reading "a voltage" or it stays in a narrow range, then the sensor portion of the O2 has in fact failed.


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Is p0052 a fuse problem or a o 2 sensor


P0052 DTC trouble code may be caused by one or more of the following:
A short in the heater circuit in the sensor.
A failed O2 sensor heater.
Wiring/connectors broken/frayed leading to sensor and/or relay.
Failed PCM/ECM.

Jan 01, 2015 | Cars & Trucks

1 Answer

1995 honda odyssey starting problems


Hello! in 1995 stored trouble codes used the On Board Diagnostic I software (OBDI)..Scanners will not work...The control unit LED can indicate any number of simultaneous component conditions by blinking separate codes, one after another...An instrument panel mounted indicator lamp will light and stay lit. If the lamp is on, or if a system malfunction is suspected even though the lamp is off, it is necessary to inspect the electronic control unit LED display. The LED display is on the ECM (ECU), which is located just below the RH side of the instrument panel. The indicator lamps operate whenever the ignition is On and a DTC is stored in the ECM (ECU) memory.
When an abnormality is detected the ECM (ECU) display blinks. The LED blinks a certain number of times, with the number of blinks indicating the number of the DTC. After the LED blinks a number of times there will be a two second pause and the LED will blink out the number of the next DTC..here are the codes..If there is a code send it to me...If there isn't a code I'll take it from there...guru.saailer

CODE DEFINITION
1 ..Oxygen Sensor "A" (Primary) defective circuit or unplugged / defective sensor

2.. Oxygen Sensor "B" defective circuit or unplugged / defective sensor

3 ...MAP Sensor (Manifold Absolute Pressure) defective circuit or unplugged / defective sensor

4... CKP Sensor (Crankshaft Position Sensor) defective circuit or unplugged / defective sensor

5.. MAP Sensor (Manifold Absolute Pressure) mechanical problem / disconnected piping
* not 94-95

6... ECT Sensor (Engine Coolant Temperature) defective circuit or unplugged / defective sensor

7... TP Sensor (Throttle Position) defective circuit or unplugged / defective sensor

8... TDC Sensor (Top Dead Center) defective circuit or unplugged / defective sensor

9... CYP Sensor (Cylinder) defective circuit or unplugged / defective sensor
* invalid code for throttle body injection Hondas
** invalid code for V6 engines

10.. IAT Sensor (Intake Air Temperature) defective circuit or unplugged / defective sensor

12... EGR Lift Sensor (Exhaust Gas Recirculation) defective circuit or unplugged / defective sensor
* invalid code for non-equipped EGR valve vehicles

13... BARO Sensor (Atmospheric Pressure) defective circuit or unplugged / defective sensor

14... IAC Valve (Idle Air Control) defective circuit or unplugged / defective sensor

15... Ignition Output Signal missing or defective ignition output signal

16... Fuel Injector System defective circuit or unplugged / defective fuel injector

17... VSS (Vehicle Speed Sensor) defective circuit or unplugged / defective sensor

19...Automatic Transmission Lock Up Control Solenoid Valve defective circuit or unplugged / defective solenoid valve

20 ..Electrical Load Detector defective circuit or unplugged / defective sensor

21... VTEC Solenoid Valve defective circuit or unplugged / defective solenoid valve
* invalid code for non-VTEC engine
** invalid for V6 engine

22... VTEC Oil Pressure Switch defective circuit or unplugged / defective oil pressure switch
* invalid code for non-VTEC engine

23... KS (Knock Sensor) defective circuit or unplugged / defective sensor
* invalid code for V6 engine

30... Automatic Transmission Signal: "A" / SEAF / SEFA / TMA or TMB defective circuit or unplugged / defective sensor
* invalid code for 1996

31... Automatic Transmission Signal "B" defective circuit or unplugged / defective sensor

41... Primary Oxygen Sensor - Heater circuit malfunction

43... Fuel Supply System defective or malfunctioning fuel supply system

45... System Too Lean or Too Rich malfunction in the fuel monitoring systems

48... LAF Sensor (Lean Air Fuel) defective circuit or unplugged / defective sensor

54... CKF Sensor (Crankshaft Speed Fluctuation) defective circuit or unplugged / defective sensor

61... Oxygen Sensor, Heated - Sensor 1 (Primary) high voltage, low voltage, or slow response

63... Oxygen Sensor, Heated - Sensor 2 (Secondary) high voltage, low voltage, or slow response

65... Oxygen Sensor Heater (Secondary) malfunctioning or defective oxygen sensor heater

67... Catalyst system Efficiency Below Threshold malfunctioning or defective catalyst system

70... Automatic Transmission malfunction with the automatic transmission controls

71... Cylinder 1 Misfire or a Random Misfire a condition is present that is creating a cylinder misfire

72... Cylinder 2 Misfire or a Random Misfire a condition is present that is creating a cylinder misfire

73... Cylinder 3 Misfire or a Random Misfire a condition is present that is creating a cylinder misfire

74... Cylinder 4 Misfire or a Random Misfire a condition is present that is creating a cylinder misfire

80... Exhaust Gas Recirculation insufficient flow detected

86... ECT Sensor (Engine Coolant Temperature) circuit range / performance problem

90... Evaporative Emission Control System leak detected in the fuel tank area

91... Fuel Tank Pressure Sensor low input

92... Evaporative Emission Control System insufficient purge flow

Dec 28, 2011 | 1996 Honda Accord

1 Answer

I HAVE A1996 FORD EXPLORER WITH CODES PO133:02,PO155:02P1115


DTC P0133 - Oxygen Sensor Circuit Slow Response (Bank1, Sensor1)
This involves the front oxygen sensor on Bank 1. This code indicates the engine air fuel ratio is not being adjusted by the oxygen sensor signal or the ECM as expected to do so, or not adjusted as often as expected to do so once the engine is warmed or under normal engine use. You will likely not notice any drivability problems, although there may be symptoms.

A code P0133 may mean that one or more of the following has happened:
The oxygen sensor is faulty
The wiring to the sensor is broken / frayed
There is an exhaust leak


DTC P0155 - 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
This code refers to the front oxygen sensor on Bank 2. The heated circuit in the oxygen sensor decreases time needed to enter closed loop. As the O2 heater reaches operating temperature, the oxygen sensor responds by switching according to oxygen content of the exhaust surrounding it. The ECM tracks how long it takes for the oxygen sensor to begin switching. It the ECM determines (based on coolant temp) that too much time elapsed before the oxygen sensor began operating properly, it will set P0155. See also: P0135 (Bank 1). You will likely notice poor fuel economy the illumination of the MIL.

A code P0155 may mean that one or more of the following has happened:
O2 Heater element resistance is high
Internal short or open in the heater element
O2 heater circuit wiring high resistance
open or short to ground in the wiring harness


DTC P0306 - Cylinder #6 Misfire Detected
A P0306 code means that the the car's computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #6. Symptoms may include the engine may be harder to start, the engine may stumble / stumble, and/or hesitate or other symptoms may also be present.

A code P0306 may mean that one or more of the following has happened:
Faulty spark plug or wire
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector
Burned exhaust valve
Faulty catalytic converter(s)
Running out of fuel
Poor compression
Defective computer


DTC P1115 - Intake Air Temperature 2 Circuit High Input (Super/Turbo Charged engines)


In the next diagram could checl this specific location about each O2 sensor...

zjlimited_8.jpeg


Hope this helps.

Oct 05, 2011 | 1996 Ford Explorer

1 Answer

I have a1996 ford explore with this codes p0133:02,po155:02,p1115andpo0306


DTC P0133 - Oxygen Sensor Circuit Slow Response (Bank1, Sensor1)
This involves the front oxygen sensor on Bank 1. This code indicates the engine air fuel ratio is not being adjusted by the oxygen sensor signal or the ECM as expected to do so, or not adjusted as often as expected to do so once the engine is warmed or under normal engine use. You will likely not notice any drivability problems, although there may be symptoms.

A code P0133 may mean that one or more of the following has happened:
The oxygen sensor is faulty
The wiring to the sensor is broken / frayed
There is an exhaust leak


DTC P0155 - 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
This code refers to the front oxygen sensor on Bank 2. The heated circuit in the oxygen sensor decreases time needed to enter closed loop. As the O2 heater reaches operating temperature, the oxygen sensor responds by switching according to oxygen content of the exhaust surrounding it. The ECM tracks how long it takes for the oxygen sensor to begin switching. It the ECM determines (based on coolant temp) that too much time elapsed before the oxygen sensor began operating properly, it will set P0155. See also: P0135 (Bank 1). You will likely notice poor fuel economy the illumination of the MIL.

A code P0155 may mean that one or more of the following has happened:
O2 Heater element resistance is high
Internal short or open in the heater element
O2 heater circuit wiring high resistance
open or short to ground in the wiring harness


DTC P0306 - Cylinder #6 Misfire Detected
A P0306 code means that the the car's computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #6. Symptoms may include the engine may be harder to start, the engine may stumble / stumble, and/or hesitate or other symptoms may also be present.

A code P0306 may mean that one or more of the following has happened:
Faulty spark plug or wire
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector
Burned exhaust valve
Faulty catalytic converter(s)
Running out of fuel
Poor compression
Defective computer


DTC P1115 - Intake Air Temperature 2 Circuit High Input (Super/Turbo Charged engines)


In the next diagram could checl this specific location about each O2 sensor...

zjlimited_7.jpeg


Hope this helps.

Oct 05, 2011 | 1996 Ford Explorer

1 Answer

I'm getting a P 1133 error code for my 2000 subaru outback limited wagon. Is it a faulty Heater circuit or an oxygen sensor? Also where are these parts located on the car? Thanks


The definition of Diagnostic Test Code (DTC) P1133 = "FRONT OXYGEN (A/F) SENSOR HEATER CIRCUIT HIGH INPUT"

Please note that DTCs (A.K.A. "fault codes") NEVER tell you what parts to replace.
The DTC here is telling you which CIRCUIT is malfunctioning. The circuit must be diagnosed to find the exact CAUSE of the malfunction.

The possible causes of this DTC are:
> Battery short circuit in harness between Engine Control Module (ECM) and front oxygen (A/F) sensor connector
> Faulty ECM

Please also note that this is NOT a typical O2 Sensor circuit. This is a 6-pin Air/Fuel Ratio sensor. Proper scan tool and datalink interface equipment is REQUIRED to properly diagnose these circuits.

Where the parts are located:
The A/F sensor is located in the exhaust pipe in front of the catalytic converter. The ECM is located Under the carpet in the passenger front foot-well area. The circuits are located between the two.

Please also Review this article:
What Else Could Be Wrong?

Sep 08, 2011 | Subaru Outback Cars & Trucks

1 Answer

Error code p0032 on town and country 3.8L engine. I replaced the bank1 oxygen sensor but still have the error code and check engine light is still on. installed brand new Bosch oxygen sensor. What else...


Causes A P0032 DTC trouble code may be caused by one or more of the following:
  • A short in the heater circuit in the sensor
  • A failed O2 sensor heater
  • Wiring/connectors broken/frayed leading to sensor and/or relay
  • Failed PCM/ECM
Possible Solutions To fix a P0032 DTC code, you'll need to do a proper diagnosis. To do that, you'll want to inspect the wiring and connectors leading to the sensor. Also if equipped with a heater relay and fuse, you'll want to check those as well. Use a digital volt ohm meter to:
  • check for 12 volts at the heater circuit feed (hint: unplug the sensor and check at the wiring connector to do this measurement)
  • check the ground circuit for continuity
  • measure the resistance of the heater circuit (done on the sensor itself)
  • measure the resistance and voltage of the wiring
Refer to a service manual for the correct specifications (volts, ohms) for your vehicle. On some Toyota vehicles this code is triggered when the resistance of the heater circuit is above 10 A.
With that said, a common fix for this DTC is to replace the air/fuel (O2 oxygen) sensor #2 on bank 1.
Please keep in mind that OEM (original equipment) replacement sensors are recommended (from the dealer). Aftermarket sensors can be less reliable and of poorer quality (not always, but more often). There's also a chance that replacement parts for the P0032 code may also fall under a federal emissions warranty (check with your dealer to see if it's covered).

Jun 29, 2011 | 2004 Chrysler Town & Country

1 Answer

Emissions egr came up on the computer test i replace it now oxygen sensor are coming up its has 4


a defective EGR valve will at time effect 02 sensor functions. But even though you vehicle does have 4 02 sensor. The DTC (diagnostic trouble code) will indicate which 02 sensor is faulty. ask the tech who performed the test on your vehicle to tell you which sensor has malfunctioned. or get the dtc code from him then google the dtc for your vehicle and you will have the answer to your question

Mar 21, 2010 | Ford Windstar Cars & Trucks

1 Answer

05 COROLLA P0031


What does that mean? A P0031 DTC (diagnostic trouble code) refers to the O2 sensor (oxygen sensor) located on Bank 1 in front of the catalytic converter. There is also an oxygen sensor behind the converter which is Sensor #2.
This O2 sensor #1 may also be refered to as an air/fuel ratio sensor since on some vehicles it is. It detects the amount of oxygen in the exhaust gas compared to the outside air and then vehicle's computer adjusts the air/fuel ratio going into the engine. The sensor is less effective when the exhaust gas temperature is low, so it includes a heater which is activated to help get better readings from the A/F O2 sensor. Essentially this P0031 code means that the resistance of the heater circuit is lower than normal. In most cases, that resistance level must fall below 0.8 A to trigger the DTC code.
Note, this code is very similar in nature to P0032, P0051, and P0052

Potential Symptoms Most likely you'll not notice any symptoms other than the MIL (malfunction indicator lamp, a.k.a. the check engine light) will illuminate.
Causes A P0031 DTC trouble code may be caused by one or more of the following:
  • A short or open in the heater circuit in the sensor
  • A failed O2 sensor heater
  • Wiring/connectors broken/frayed leading to sensor and/or relay
  • Failed PCM/ECM
Possible Solutions Need an O2 Sensor? Visit our O2 Sensor shopping area for the lowest price on your replacement sensor!
To fix a P0031 DTC code, you'll need to do a proper diagnosis. To do that, you'll want to inspect the wiring and connectors leading to the sensor. Also if equipped with a heater relay and fuse, you'll want to check those as well. Use a digital volt ohm meter to:
  • check for 12 volts at the heater circuit feed (hint: unplug the sensor and check at the wiring connector to do this measurement)
  • check the ground circuit for continuity
  • measure the resistance of the heater circuit (done on the sensor itself)
  • measure the resistance and voltage of the wiring
Refer to a service manual for the correct specifications (volts, ohms) for your vehicle. On some Toyota vehicles this code is triggered when the resistance of the heater circuit is below 0.8 A.
With that said, a common fix for this DTC is to replace the air/fuel (O2 oxygen) sensor #1 on bank 1.
Please keep in mind that OEM (original equipment) replacement sensors are recommended (from the dealer). Aftermarket sensors can be less reliable and of poorer quality (not always, but more often). There's also a chance that replacement parts for the P0031 code may also fall under a federal emissions warranty (check with your dealer to see if it's covered).

Aug 20, 2009 | 2006 Toyota Corolla

1 Answer

1996 Miata - P1170 code - What is this code?


DTC - P1170 Explanation: HO2S Bank 1 Sensor 1 Circuit Fixed (Bank 1 Sensor 1)

An HO2Sensor is an oxygen sensor, or lambda sensor. The DTC tells you the Sensor is defective.

Oct 20, 2008 | 1996 Mazda MX-5 Miata

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