The upstream orange O2 sensor wire harness connectors on my vehicle were both torn off by the thieves who stole my catalytic converters. I have replacement connectors with pigtails ready to go, but I do not know which color wire goes in which hole in the connector on either side. The passenger side wires still have the metal tips attached--two are gold, two are silver (see photo). The metal tips are missing on the driver's side, but I have replacements. The colors of the wires coming from the harness given in the diagrams in the RAVE manual are completely different from mine. Is it true that the color configuration of the downstream O2 sensor connector is the same as the upstream on both sides?

Thanks in advance.


Right O2 sensor harness wires without plastic connector

 

Your wires match the colors in the manual exactly for connector C0645. There is a diagram showing position, it is in the RAVE electrical library, wiring diagram show the same.

 

Don't forget that you can't solder any of these wires, they must be crimped if you need to splice anything.

 

Why is that? Just curious.

 

To clarify, it's ok to solder the copper body-side wiring, which is more relevant to this thread. There are multiple theories on why crimping is the preferred method between the connector and the sensor; from solder changing the resistance across the wiring, the wire being stainless and hard to solder, and the sensor itself getting its reference oxygen values from the wiring to generate the voltage signal for the ECU. Don't just take my word for it however, throw it into the googler.

 

Thanks to all for the advice.

I refitted the new connector on the right side, which intermittently works. The left wires have no metal connector tips and they are short and hard to access which made stripping the hardened insulation and splicing them to a pigtail connector (wire color mapping following Electrical Library diagrams) difficult. The left sensor fails to read and has generated an avalanche of fault codes including:

Current
P0102 MAF circuit low input
P0340 Camshaft position sensor
P0445 Evap Purge control valve shorted
P0448 Evap Purge vent control shorted
P0134/P0154 No O2 sensor activity both sides

Pending
P0135/P0141/P0155/P0161 O2 sensor heater both sides front and back
P0300 Random misfire

Disconnecting the left connector clears the pending codes.

I am going to remove the upper inlet manifold and coils and resplice the sensor wires. Could the MAF, Evap System and Camshaft codes be caused by bad O2 sensor wire connections? I will also try a different O2 sensor to see if the current one was damaged. If there are better ways to proceed, I look forward to hearing them.

 

The ECU will adjust the mixture according the the O2 feedback from the front two sensors. If the O2 sensor(s) is providing bad intel to the ECU then it will be trying to compensate accordingly and will likely use incorrect fueling maps which would cause the misfire and possibly MAF codes.I wouldn't think you'd get EPV shorted codes unless there was an actual wiring short but I don't know enough about those codes. I wouldn't think the CPS codes would be triggered by faulty O2 info either but it may simply be saying the info coming from the CPS isn't what it was expecting, based on the wacky O2 feedback. You may have to do some careful splicing further back to get solid connections.

 

Bad Maf will throw the other codes. Disconnect the MAF, disconnect your oxygen sensors, then reconnect one at a time while watching the charts to determine if each is working. Replace one at a time.

 

1. Thanks for your replies. If the truck really had all the MAF/EVAP/Camshaf/O2 sensor issues at once, it wouldn’t run oule seem to be the ECM is receiv sketchy

How difficult would it be the replace the engine wire harness? The can be had on eBay used for $100. That would guarantee the O2 sensor connectors and wires would all be stock/intact. I was planning on removing the upper intake and coils to resplice anyway. I’m not sure any splicing of those small gauge, brittle wires is likely to yield a good connection.

 

Swapping the harness is tedious, but not impossible. Having a complete, unmolested harness on the truck has a lot of value so it may be worth the effort. Thinking about all the connectors (and I've only done this once, with the engine out), you will want to remove the upper intake mani to gain better access to the injectors and the coils, but I can't think of anything that's a showstopper. CPS, CKPS, oil pressure and knock sensors will be the biggest PITA. Take your time and maybe label things as they come off and move the labeling to the new harness before you install, although I didn't bother doing this. It's pretty self explanatory due to the length of the various connectors and the locations of all the sensors. The injectors and the EVAP/IAC area being the only exceptions since connectors are many and similar, and can easily reach sensors they don't belong on. The most important piece will be making sure the seller knows what he has and it's a compatible harness; consider SAI and that connector at the bottom of the radiator which is found on some years and not others.