Engine Codes P0155,P0135

[Dave4.6]

I figured out my obd port and pcm couldn't talk due to a wire at the fuse box now I have these two codes for the O2 sensors can someone tell me where to locate the harnesses, I want to check the wiring and voltage before I just replace the sensors

 

[wmburns]

Anytime the PCM calls out a "circuit Malfunction" this means there something soooooooooooooooo wrong with the circuit that the PCM is unable to perform any diagnosis.

Considering that you have a DTC for both O2 sensors I wouldn't think "bad O2" sensor. Instead think "common cause". IE, power.

Do you have any other DTC codes? Have you confirmed that fuse F2.8 has key on power in and out? If the fuse is good, suggest confirming good voltage and ground at the O2 heater circuit. Best to use a test light that will "load" the circuit.

1999-2004 MY fuse panel schedule:

1999 Mustang GT with 2001 motor swap, wont fire. Please help

First off thank you for taking the time to read this, I hope that you will be able to help me out in some way to get a 4 month project off the ground and back onto the streets. I'm not a master mechanic but know just a little bit, enough to do your typical maintenance, overhauls, and swaps. I...

www.allfordmustangs.com

OBTW, it would be handy to mention the model year and engine of the Mustang in question. Saves the people trying to help from guessing.
>>

P0135 - HO2S Sensor Circuit Malfunction (HO2S-11) ​ P0155 - HO2S Sensor Circuit Malfunction (HO2S-21) ​ ​ During testing the HO2S Heaters are checked for opens/shorts and excessive current draw. The test fails when current draw exceeds a calibrated limit and/or an open or short is detected. ​ Short to VPWR in harness or HO2S. Water in harness connector. Open VPWR circuit. Open GND circuit. Low battery voltage. Corrosion or poor mating terminals and wiring Damaged HO2S heater. Damaged PCM. Possibly reasons: ​ Wiring. Damaged HO2S heater. Damaged PCM.

 

[Dave4.6]

its a 1997 4.6 gt I didnt nention the p1405 ,now a new code p1151 I drove it this morning for about 80 miles car ran fine no studder no shudder

 

[wmburns]

If this were my car I would be checking for power's and grounds (5 volt and 12 volt) to the O2's and DPFE sensor. Verify that the O2 heaters actually work. Verify that the O2 sensor signal is switching.

Do you have an ODB2 scanner? If so, this could make short work of your problem. Here's some information on an affordable ($30) Windows based unit.

ForScan ODB2 scanner w ELM327 USB

ForScan ODB2 scanner w ELM327 USB

While working on your car have you ever wanted: to find an ODB2 operational PID value (say fuel pressure or MAF)? How about graph a PID value over time? Or compare multiple PID's over time? Access a bi-directional PCM control such as test a...

www.stangnet.com

P1151 - Lack of HO2S-21 Switch, Sensor Indicates Lean ​ Electrical: Short to VPWR in harness or HO2S Water in harness connector Open/Shorted HO2S circuit Corrosion or poor mating terminals and wiring Damaged HO2S Damaged PCM Fuel System: Excessive fuel pressure Leaking/contaminated fuel injectors Leaking fuel pressure regulator Low fuel pressure or running out of fuel Vapor recovery system Induction System: Air leaks after the MAF Vacuum Leaks PCV system Improperly seated engine oil dipstick EGR System: Leaking gasket Stuck EGR valve Leaking diaphragm or EVR Base Engine: Oil overfill Cam timing Cylinder compression Exhaust leaks before or near the HO2S(s)

 

[Dave4.6]

If this were my car I would be checking for power's and grounds (5 volt and 12 volt) to the O2's and DPFE sensor. Verify that the O2 heaters actually work. Verify that the O2 sensor signal is switching.

Do you have an ODB2 scanner? If so, this could make short work of your problem. Here's some information on an affordable ($30) Windows based unit.

ForScan ODB2 scanner w ELM327 USB

ForScan ODB2 scanner w ELM327 USB

While working on your car have you ever wanted: to find an ODB2 operational PID value (say fuel pressure or MAF)? How about graph a PID value over time? Or compare multiple PID's over time? Access a bi-directional PCM control such as test a...

www.stangnet.com

P1151 - Lack of HO2S-21 Switch, Sensor Indicates Lean ​ Electrical: Short to VPWR in harness or HO2S Water in harness connector Open/Shorted HO2S circuit Corrosion or poor mating terminals and wiring Damaged HO2S Damaged PCM Fuel System: Excessive fuel pressure Leaking/contaminated fuel injectors Leaking fuel pressure regulator Low fuel pressure or running out of fuel Vapor recovery system Induction System: Air leaks after the MAF Vacuum Leaks PCV system Improperly seated engine oil dipstick EGR System: Leaking gasket Stuck EGR valve Leaking diaphragm or EVR Base Engine: Oil overfill Cam timing Cylinder compression Exhaust leaks before or near the HO2S(s)

 

[Dave4.6]

Thanks for all the help,got those p0155 0135 codes worked out down to the last p1405 its the little pipe off the egr pipe broke off
will try to fit another in or jb quick it