I respliced the O2 sensor wires and put it all back together. Tested it—same 7 (pending) codes as before. Following advice given above, I disconnected the O2 and MAF sensors. Reconnected O2s with no MAF and all codes cleared. Looks like I have a bad MAF sensor. I have all symptoms associated with MAF sensor failure: vehicle stalls right after starting, smoky exhaust, strong fuel smell, etc. Any suggestions on replacements?

The connector shown in the RAVE diagram is just above the cruise control module. The caption says “disconnect engine harness to main harness multiplug” so I’m not sure what that is supposed to mean but hopefuly I will not have to remove the harness.

Where can I get a replacement for that red plastic locking gasket on the plenum?

Thanks again.

 

Just go with whatever is lowest cost, no significant durability difference and the engine ecu only really uses it in quick throttle transitions and when the oxygen sensors are dead.

 

thanks for your valued assistance. happy holidays.

 

Update: I replaced the MAF sensor and got the same boatload of pending fault codes:

P0134, P0154 O2 sensors no activity. There are receiving .4 V each
P0445 and P0448 (evap emission purge control valve and vent control) both say circuit shorted.
P0102 MAF circuit low input
P0340 Camshaft Position Sensor

Can poor spliced connector wires cause all these problems?

With the new MAF sensor no more fuel smell or smoky exhaust so it appears to be working correctly even if it didn't solve my code problems.

 

Just had a similar thing happen to me, truck threw a ton of codes, 135, 155, 134, 1884, 154, 102. Swapped in known good MAF's and oxygen sensors (good to have multiple trucks), same thing. Unplugged the appropriate plug from the ECU and checked the four 02 wires to ground to make sure they were not shorted (none were). Turns out it was a bad ECU, swapped in a different ECU and all was good. This truck ran fine before pulling the engine and dropping in a rebuilt one, no idea why the ECU suddenly went bad.

You can buy a use ECU, BCU, Inst. Cluster on ebay, throw it in and see if it solves your problem, if it doesn't just resell it on ebay and you are out nothing but shipping.

 

in continuation ... with new MAF installed and the two O2 sensors installed, all the codes mentioned above persisted. I then disconnected driver’s side O2 sensor (this is the spliced harness side) and all codes cleared but one—P1884. I cleared the code and connected an old O2 sensor on the driver’s side (with the new sensor connected on the passenger side) and ALL the codes cleared themselves. This suggests that the new driver’s side O2 sensor was bad out of the box or (if this is possible) damaged when connected to first bad spliced pigtail. The replacement O2 sensors are made by Walker, by the way. The old one currently connected is Brand X from eBay. I need to get the vehicle smog checked immediately so I will defer further swapping around of sensors/testing until it passes and replace the bad one with the same.

In the event that the problem recurs . . . would I have to replace the ECM, BCM and instrument cluster all together and do those three units have to be from the same donor vehicle? Isn’t there some dealer re-initialization ritual that has to be performed?

 

The ECM, BCM, Instrument Cluster and the interior fuze box all need to be from the same vehicle.

But, there are some work arounds.

Fusebox - Part of the fusebox communicates with the BCM. If you swap either the red light in the middle of the instrument panel will come on and the engine will not start. But if you leave in the key in the II position for 5 minutes the new BCM and the fusebox will synch them selves together.

Instrument Cluster - The milage is kept in the BCM and the instrument cluster. If you have swapped either the milage will be different so the instrument clusters milage will blink. This blinking can be turned off with a Nanocom. The milage in the BCM will still be different than the instrument cluster but without the blinking no one real really know.

There is a way to synch the milage from the BCM to the instrument cluster with a Nanocom but there are some rules within the Nanocom that makes it impossible in some circumstances. You can not synch a lower milage BCM's to a higher milage instrument cluster. And you can not synch a BCM's milage to an instrument cluster with higher milage if the difference between the two are 30,000 miles or lower.

Note: You can Synch an ECM with a different BCM with a Nanocom. But in my past try I was unsuccessful. Easiest thing to do is get a matching set of BCU and ECM and get a Nanocom to turn off the blinking in the instrument panel. You will need that same Nanocom to re-program your Fob keys. Other than waiting for the BCU and the fusebox to re-synch it's basically plug and play.

Also, in the Rave Workshop Manual the Engine computer is normally referred to as the ECU.

 

The driver’s side O2 sensor connector is spliced to the engine harness. Could a bad connection cause all these diverse sensor codes?

I replaced the MAF and tested it against the current O2 sensors and a few old ones, getting inconsistent codes/no codes. The truck nearly stalls everytime the engine is started, then runs alright. Could bad O2 sensors cause all the sensor codes?

Two of the codes refer to a purge valve shorted circuit. Is this likely to be the case or are these codes the results of bad MAF or O2s? Is it a grounding problem or is the purge valve dead? I can buy the Hyundai purge valve for $20.

Or is replacing the ECM/BCM/IC etc obviously the solution?

All this because my catalytic converters were stolen and sold to a junk dealer for $50.

Thank you.

 

Have you traced the wires to the ECU to check for shorts? I'd do that before buying more parts, especially since the ECU is reporting shorted circuits. It might be worth swapping the ECU too.

 

I'm with Ahab. I'd buy an electric multimeter with long leads so you can check continuity for the wires between the connection to the O2 sensors and the ECU. If anything they are a great tool to have for various reasons in the future.

It will be a two man job but first the establishment of the wires needs to be confirmed before buying or swapping parts.

If your ECU was not bad before the thieves cut the cats out most likely it is still good.

Also, FYI. I've had a bad O2 sensor and a bad ECU.

In my case the bad ECU's voltage for the O2 sensor code it was reading was maxed out. They are supposed to stay under .999. Mine would go over 1.250 and then the Service Engine Soon light would come on.

For the bad O2 sensor the voltage reading would hover around .450. If it does not move less than .430 or so or get higher than .470 or so the Service Engine Soon light will come on.

Per your 12/23 post if you are only getting .4 then it's either the O2 sensors or the wiring. Although bad O2 sensors out of the box can happen odds are its the wires. Again, check for continuity.

Hope this help out.