Where the heck is it? I have the Chilton's guide, which is, of course, no help. It shows a fuse, but it doesn't say which one or where to find it. I searched and found lots of wiring diagrams online, but none of them say which fuse or where it is. I found one that showed a relay, but again, no clue as to where to find it. I had codes for all three O2 sensors, and with 60K on it, I decided just to change them all. Reset all the codes, but P0135, P0141, and P0155 all came back immediately. These are the codes for the heaters on each of the 3 sensors. I have no voltage to the heater circuits, so I am trying to find the fuse (or fusible link?)
Any help GREATLY appreciated!

Thanks!!!

 

The power comes from fuse "C" in the engine compartment fuse relay panel and then through the PCM Power Relay in the engine compartment fuse relay panel. In your van both are good or you would have no codes at all and the engine would not run.

Diagnostic Trouble Codes (DTCs) P0135, P0141, P0155 and P0161 indicate a short to ground, open, or short to VPWR in the HO2S heater circuit.

Possible causes:

Shorts to B+ in harness or HO2S.
Water in connectors.
Cut or pulled wires.
Disconnected wiring.
Open VPWR circuit.
Open GND circuit.
Low battery voltage.
Corrosion or poor mating terminals.
Damaged PCM.

I do not know what engine/transmission you have so I can not give you any more information or wiring diagrams/wire locations.



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Thanks! Mine is a 5.8, E4OD. I reseated the relay, and it seemed to get power back, but the 0155 code keeps coming back. WIth the battery disconnected, I read about 6 ohms of resistance between the red wire, and the red/white wire on the bank one sensor plug, with the O2 sensor unplugged, and with or without the PCM relay being plugged in. The Bank 2 side showed about 168 K Ohms. I disconnected the PCM itself, and the resistance showed as an open, and when I plugged everything back in, the 6 ohms had changed to around 168k, which is about what the bank 2 side read. Hopeful that reseating the connector fixed it, I started it back up, but the code came back immediately. I have not retested the plug for resistance, but my gut says it's back to 6 ohms. I'm guessing that the PCM creates a connection on some other circuit, to which the red or red wire is shorted, and that is the 6 ohms I am seeing. Unplugging the PCM disconnects it, but then the PCM reconnects on startup. It's either that, or the PCM maintains ground on the red/white, even with the battery disconnected until the connector is removed(which I very seriously doubt) I did notice that the wires at the O2 sensor plug were slightly melted, but only enough to stick the insulation together, no bare wires. I'm guessing that the old O2 had shorted at the heater, and caused the issue I have now. That red wire connects to S151, which seems to be just a junction, but I'm not sure what it looks like, or where it's physically located. I plan on just cutting that wire from the junction, and from the O2 sensor, and running a new wire, but I first neet to find that junction. I also need to see if I can find the short, to see if it may have shorted other wires as well. If you know where I can find that junction (S151), that would help a LOT!
Thanks!!

 

Location of S151:

S151, Gasoline With Speed Control
Engine control sensor harness, near T/O to C180

S151, Gasoline Without Speed Control
Engine control sensor harness, near T/O to C121



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OK, Thanks! Is this just going to be a bunch of wires soldered together, or a terminal strip? Not sure where the T/O to C180 is, either. Does it give you a physical location?

Again, thanks VERY much for all the help! Do you think I'm on the right track?

 

Sorry I have not looked at your problem close enough to tell you if you are on the right track or not.

C180 is the plug for the speed control servo. The T/O (Take Out) point is the T/O in the diagram below. Near the T/O point would be where the XX are in the diagram.
Yes a splice is a bunch of wires soldered together inside the harness.




/

 

Thanks again! I'll check out the wiring around that junction tomorrow, and let you know what I find. I do still need to check that, but things have changed. I got a chance to check the resistance, and it's still showing an open, and the O2 sensor is reading 3.7 ohms across the heater. I now have 12 volts at the heater, with it lugged in, but I am still getting the P0155. Even though the sensor tests good with an resistance check, I'm still going to swap it with the other side, and see if the code follows. If not, I'm going to recheck all of the voltage and resistance measurements, providing the check of the wiring near that junction doesn't reveal any problems.

 

H30 DTCS P0135, P0141, P0155 AND P0161: HO2S HEATERSIGNAL CIRCUIT IS
OPEN, SHORTED TO GROUND, SHORTED TO B+ OR EXCESSIVECURRENT DRAW
Diagnostic Trouble Codes (DTCs) P0135, P0141, P0155and P0161 indicate a short to ground, open,
or short to VPWR in the HO2S heater circuit.
DTC/HO2S Reference List:
DTC P0135 = HO2S HTR-11
DTC P0141 = HO2S HTR-12
DTC P0155 = HO2S HTR-21
DTC P0161 = HO2S HTR-22
Possible causes:

Shorts to B+ in harness or HO2S.

Water in connectors.

Cut or pulled wires.

Disconnected wiring.

Open VPWR circuit.

Open GND circuit.

Low battery voltage.

Corrosion or poor mating terminals.

Damaged PCM.
 Visually inspect the HO2S circuit for exposed wiring, contamination, corrosion and proper assembly.
Note: On some applications, a vehicle hoist may be required to access the HO2S harness.
Were any concerns found during the visual inspection?
H31 PERFORM KEY ON ENGINE OFF (KOEO) SELF-TEST
 Key off.
 Scan Tool connected.
 Key on.
 Engine at 2000 rpm for 5 minutes.
 Key off.
 Key on, engine off.
 Activate KOEO Self-Test.
Are DTCs P0135, P0141, P0155 and/or P0161 present?
Yes No
REPAIR any concerns found in the visual
inspection. RERUN Quick Test .
GO to H31 .
Yes No
No DTCs present. FAULT may be intermittent.
H32 CHECK FOR VPWR AT THE VEHICLE HARNESS CONNECTOR
Note: If DTCs P0135 and P0155 or P0141 and P0161 are displayed, both heater circuits will require
testing. DTCs displayed separately are tested individually.
 Key off.
 Disconnect the appropriate HO2S(s).
 Inspect both ends of the connectors for damaged or pushed out pins, moisture, corrosion,
contamination, etc. Service as necessary.
 Key on, engine off.
 Measure the voltage between VPWR and SIG RTN circuit at the HO2S vehicle harness connector(s)
(refer to Schematic at the beginning of this Pinpoint Test).
Is the voltage greater than 10.5 volts?
H33 CHECK FOR OPEN VPWR CIRCUIT
 Key off.
 Install breakout box, PCM disconnected.
 Suspect sensor disconnected.
 Measure the resistance between the VPWR Test Pin atthe breakout box and VPWR at the HO2S
vehicle harness connector.
Is the resistance less than 4.0 ohms?
H34 CHECK HO2S HEATER RESISTANCE
 Key off.
 HO2S disconnected.
 Connect DVOM to HO2S HTR GND and VPWR Test Pins at the HO2S sensor connector, and
measure the resistance.
Is the resistance between 3 and 30 ohms?
GO to H32 .
GO to Pinpoint Test Step Z1 with the following
data: HO2S PIDs and a list of possible causes.
Yes No
GO to H34 . GO to H33 .
Yes No
GO to H34 .
CHECK fuse in circuit. If fuse is OK, REPAIR
open circuit. REMOVE breakout box.
RECONNECT all components. RERUN Quick
Test .
H35 CHECK FOR HEATER GND AND VPWR SHORTED TO HO2S CASE
 Suspect sensor disconnected.
 Measure the resistance between the HO2S Heater GND at the HO2S connector and the HO2S case.
 Measure the resistance between the HO2S Heater GND connector and the Signal RTN Pin.
 Measure the resistance between the HO2S VPWR at theHO2S sensor connector and the HO2S
sensor case.
Is the resistance greater than 10,000 ohms?
H36 CHECK FOR SHORTS TO OTHER GROUNDS AND VPWR IN THE HO2S
HEATER GROUND HARNESS CIRCUITS
 Key off.
 Disconnect Scan Tool from DLC.
 Suspect sensor disconnected.
 Disconnect PCM.
 Breakout box installed, leave PCM disconnected.
 Use the following list to measure the resistance between the appropriate test pins at the breakout
box.

DTC P0135 = HO2S HTR-11 (HTR GND)

Test Pin 93 and Test Pins 24, 76, 103, 91 and 97.

DTC P0141 = HO2S HTR-12 (HTR GND)

Test Pin 95 and Test Pins 24, 76, 103, 91 and 97.

DTC P0155 = HO2S HTR-21 (HTR GND)

Test Pin 94 and Test Pins 24, 76, 103, 91 and 97.

DTC P0161 = HO2S HTR-22 (HTR GND)

Test Pin 96 and Test Pins 24, 76, 103, 91 and 97.
Is the resistance greater than 10,000 ohms?
Yes No
GO to H35 .
REPLACE HO2S. REMOVE breakout box.
RECONNECT all components. RERUN Quick
Test .
Yes No
GO to H36 .
REPLACE HO2S. REMOVE breakout box.
RECONNECT all components. RERUN Quick
Test .
Yes No
GO to H37 .
REPAIR shorted circuit. REMOVE breakout
box. RECONNECT all components. RERUN
Quick Test .
H37 CHECK FOR OPEN HO2S HEATER GROUND HARNESS CIRCUIT
 Key off.
 Suspect sensor disconnected.
 Breakout box installed, PCM disconnected.
 Use the following list to measure the resistance between the appropriate test pins at the breakout box
and the HO2S HTR GND at the vehicle harness connector.

HO2S HTR-11 Test Pin 93 (HTR GND)

HO2S HTR-12 Test Pin 95 (HTR GND)

HO2S HTR-21 Test Pin 94 (HTR GND)

HO2S HTR-22 Test Pin 96 (HTR GND)
Is the resistance less than 4.0 ohms?
Yes No
Open or shorted or excessive resistance in the
heater circuit in the PCM. REPLACE PCM.
REMOVE breakout box. RECONNECT all
components. RERUN Quick Test.
REPAIR open or excessive resistance in the
heater circuit in harness. REMOVE breakout
box. RECONNECT all components. RERUN
Quick Test .

 

Thanks VERY much for all of the help, everybody! Well, when I saw the 12 volts at the red wire on the heater, I was measuring between the red wire, and ground. Measuring between the red and red/white, I saw nothing. I checked again near the firewall connector from the PCM, and still nothing. Just to cover all of my bases, I tested between the battery + and the red/white, and still nothing. I did find S151, and it looked good, as did all of the other wire on that circuit. I'm guessing my PCM is toast. I can only speculate that the old O2 heater sensor shorted, and fried it. Is there anything else I missed, that you guys can think of? I guess the good news is, it's "only" $125. Fairly painless for a PCM, I suppose. Well, at least I got it figured out, thanks to all of you!
Thanks again!!

 

A bit late to this thread but here's a factory manual for wiring etc, aka EVTM or Electrical-Vacuum Troubleshooting Manual. Has a lot of extremely useful information, they come in so handy you'll wonder how you ever got along without one!

This one is in good condition and cheap too: 1996 Econoline Club Wagon Van Wiring Diagrams Electrical Vacuum Manual Evtm | eBay

HTH

 

But I'm just now getting the time to get back to work on this. I have another question: where is the odometer reading stored, in the ECU or the cluster? My van only has about 60K on it, and i don't want an ecu with a crapload of miles on it.
Thanks!!

 

The miles are stored inside the PSOM.
The PSOM module location is inside the cluster but can be removed and installed in another cluster.

 

Awesome, thanks for the great news!

 

Hi All! Sorry so long in getting back to this, but I just got it fixed about a week ago. We don't drive it much, and i had bigger priorities. Anyway, I replaced the computer, and all is well. Evidently, one or more of the old O2 sensors shorted, and burned out the computer.

I just want to say a huge THANK YOU to all who helped. Love this site!!

Cheers!!

 

I am having the exact same problem with a 1996 F-350 460 7.5
I replaced all three 02 sensors and all three still code. I have read and understand this thread. Question is, does this thread still apply to my make & model and is there any other advise ? This forum rocks !