Can an ECU expert please weigh in on my situation.

I had a MAF issue. Initially 3 codes: P0102 (MAF), 135 (O2), 155 (O2)

While waiting for a new Bosch MAF sensor, I noticed that I hadn't heard the SAI pump in some time, so decided to troubleshoot it (stupid move #1).

Not knowing which relay controlled the SAI pump, I started with the SM relay (R2). The blades are labeled 1-2 (solenoid control signal) and 3-5 (power circuit/path). Not sure why these relays use a 1,2,3,5 numbering rather than the more conventional 30, 85, 86, 87 (and 87a) convention.

(Stupid move #2), I think I jumpered 3 (or 5, I can't remember, but it was the one with 12v on it) to 1 or 2 (again I can't remember) on the SM relay (R2).

The jumper (a paperclip) heated up like a light bulb filament before I could pull it out -- I have the burn marks on my fingers to prove it.

Once the pain subsided a bit on my fingers, I actually looked at the diagram embossed on the relay, then jumpered 3 and 5 and the starter motor cranked, so SM = starter.

I would have assumed the key was in the blade 1-2 path, so when I put the bus voltage on the ground side of the 1-2 path, it drew the current that heated the jumper up to a red glow. But maybe the key circuit also goes thru the ECM somehow.

While nursing my burnt fingers, I came back to the forum,and someone on the forum then pointed me to the R6 relay (one of the two motor-thunderbolt relays) and I was able to determine that the SAI was good by jumpering the 3-5 to force it to run.

However, going back to the ODBII, I discovered I now have 15-18 codes instead of just the 3. I cleared them and they came right back.

All of those codes except the original 102 (MAF signal low), 135 and 155 (O2 heater, which I think relate to the bad MAF) all relate to a short circuit for the SAI, EVAP purge and EVAP test valves, the crank position sensor and the coolant temp light, and no signal from the O2 sensors.

As it's my understanding that the way the ECM controls the relays is that it opens a path to ground on 1 or 2 pin in order to actuate the relay solenoid, I am wondering if I somehow dumped a bunch of current into the ECM control circuitry and fused or fried either some shared ground in the fuse box, the PCB itself inside the ECM or the ground wire to the ECM (or something else).

So two questions:

1. How would I troubleshoot/isolate this to the fuse box, ECM or ECM ground?

2. If I did fry the ECM, is this a plug-and-play replacement or does it require programming with some special tool I am assuming programming is involved as the ECM appears to have the vehicle VIN loaded into it).









Car Scanner ELM OBD2
DTC report
============1==============
P0102
Raw code: 0102
ECU: OBD-II
Status: Confirmed
OBDII: Mass air flow (MAF) sensor/volume air flow (VAF) sensor - low input

============2==============
P0135
Raw code: 0135
ECU: OBD-II
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 1, bank 1, heater control - circuit malfunction

============3==============
P0155
Raw code: 0155
ECU: OBD-II
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 1, bank 2, heater control - circuit malfunction

============4==============
P0141
Raw code: 0141
ECU: OBD-II
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 2, bank 1, heater control - circuit malfunction

============5==============
P0161
Raw code: 0161
ECU: OBD-II
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 2, bank 2, heater control - circuit malfunction

============6==============
P1451
Raw code: 1451
ECU: OBD-II
Status: Confirmed
OBDII: Evap Emission Control Sys Vent Control Valve Circuit

============7==============
P0414
Raw code: 0414
ECU: OBD-II
Status: Confirmed
OBDII: Secondary air injection (AIR) solenoid A - short circuit

============8==============
P1482
Raw code: 1482
ECU: OBD-II
Status: Confirmed
OBDII: SCP

============9==============
P0445
Raw code: 0445
ECU: OBD-II
Status: Confirmed
OBDII: Evaporative emission (EVAP) canister purge valve - short circuit

============10==============
P0448
Raw code: 0448
ECU: OBD-II
Status: Confirmed
OBDII: Evaporative emission (EVAP) system, vent control - short circuit

============11==============
P0340
Raw code: 0340
ECU: OBD-II
Status: Confirmed
OBDII: Camshaft position (CMP) sensor A, bank 1 - circuit malfunction

============12==============
P0134
Raw code: 0134
ECU: OBD-II
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 1, bank 1 - no activity detected

============13==============
P0154
Raw code: 0154
ECU: OBD-II
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 1, bank 2 - no activity detected

============14==============
P0139
Raw code: 0139
ECU: OBD-II
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 2, bank 1 - slow response

============15==============
P0159
Raw code: 0159
ECU: OBD-II
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 2, bank 2 - slow response

============16==============
P0140
Raw code: 0140
ECU: OBD-II
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 2, bank 1 - no activity detected

============17==============
P0160
Raw code: 0160
ECU: OBD-II
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 2, bank 2 - no activity detected

============18==============
P1884
Raw code: 1884
ECU: OBD-II
Status: Confirmed
OBDII: Engine Coolant Level Lamp Circuit Short to Ground

 

The ECU is plug and play sort of. You need the matching BCU for it to be plug and play, and then you need to turn the ignition to position 2 for 30 minutes to sync it with the inside fusebox. Even then, the odo will flash unless you also install the matching instrument cluster. If you move the car even a foot with it flashing it will be like that unless you turn it off with a nanocom. So to actually be plug and play you need the ecu, bcu, ic, and inside fuse box. I keep a few around for troubleshooting. You can get them from ebay, forum breakers like Paul Grant, or facebook guys like Will Tillerey or Doc Heydary

That said, you can troubleshoot each of the circuit codes by disconnecting the ECU plugs and the sensor plug and checking for ground shorts and voltage. But given all the codes arriving suddenly, you likely fried either the ECU or fusebox or both. Good one! I have not seen this before.

Good luck

 

Thanks, I guess if you are going to f**k up, you may as well do it well.

I finally looked at the pinout of the ECU in the RAV and it looks like I got a code for about every system that uses a path to ground for solenoid/relay actuation, so I am guessing more and more that there is a common ground bus in the ECU that I smoked -- but if I did, wouldn't it show an open and not a short (that's the part that confuses me).

Lots of questions, will try to keep each short.

What is the "ic"?

When you say swap out fuse box, are you referring to the engine compartment fuse box, as I have a spare one of those I can try and swap in?

The inside fusebox is "smart", i.e., it is somehow digitally matched to the ECU?

And the BCU is also digitally matched to the ECU?

Can the ECU-BCU-IC-Fuse Box be matched using a T4(?) tech tool. If I have to take it to someone to do that rather than replace all those units, I will.

My vehicle is an SAI model, it came from CA, were there NAS SAI and non-SAI vehicles in 2004?

And there are SAI and non-SAI ECUs, right?

If I end up having to go the replace the ECU-BCU-IC-Fuse Box route, can I also do an SAI delete at the same time -- and still pass inspection in Texas?

Though we've gotten more than our money's worth out of it (it was blown up when we got it but free), this D2 has a lot of sentimental value so want to try and save it if possible (was given to my son with a slipped sleeve, he rebuilt engine himself with top hats and then drove it thru senior year of high school and four years of college with only the usual small issues, MAF, battery, water pump, coils, etc.)

(FYI, my son is also BSME, now doing a PhD)

 

Can you pull the ECU, open it up and look for an obvious burn mark?

 

I am going to go at it this weekend, and pulling and popping open the ECM will be part of that (though as I've seen D2s driven thru water up to the roof, I am assuming that it is a hermetically sealed waterproof unit and can't be opened, but who knows, maybe they just use a bunch of o-rings to keep water out).

Pretty easy to spot a surge on a PCB: I've seen it on my home's air handling units (we have unreliable power here in Austin and I've lost TVs, HVAC control boards, etc. to power surges), and on some Porsche controller units in some of my other cars.

But right now I am assuming I will need to do the ECU+BCU+Instrument Cluster changeout.

These "kits" -- ECU+BCU+Instrument Cluster -- go for $150-200 on eBay, but there's no mention by any of the sellers of needing a matching/mated IC, so waiting to hearing what that is (is IC an integrated control module?).

Fortunately, the only subsystems affected according to the codes are emissions-related, so the beast still starts and can at least be moved around.

 

IC is instrument cluster. If you look at my post I said " So to actually be plug and play you need the ecu, bcu, ic, and inside fuse box".

The ebay sellers are not including the inside fusebox beccause you can easily sync it to the others by turning the key to position 2 for 30 minutes after install.

The good thing about getting an ebay set is you can use it to test, and if you don't need it just resell it for what you paid for it.

 

Instrument cluster

Could be either, but I would lean more heavily to it being underhood.

Yes, it is smart and matched to the ECU/BCU. You can sync it by turning the key switch to position 2 for 30 minutes without starting.

Yes

Yes, it can.

Yes

Yes

Yes, as long as they don't use the VIN to pull the emissions equipment data which I find hard to believe on a 20 yo vehicle.
Congrats, no reason to give up on it now, they are just getting valuable.

 

Agreed, Some D2s have gone for nearly $30K on BAT.

Thanks for clarification on IC. I can be OCD sometimes, and in the RAV, they call it an Instrument Pack.

So I am going to first swap out the engine fuse box, then test all the control wiring tonight or tomorrow. If I didn't fry any wiring in the harness, then I going to buy an ECM-BCU-IP "kit" on eBay.

As I assuming that I am more than likely doing the ECM swap out (hope for the best, plan for the worst), what are your thoughts on getting a 99-02 ECM kit instead and just removing the SAI? Too risky? just keep the SAI?

BTW, I noticed that my condenser fan is now running all the time, even when ambient temp was in the 50s; as that relay is also energized by the ECM taking it to ground, so I am assuming that I fried/fused that ECM pinout permanently to ground as well. (this wouldn't throw any codes, but I am nonetheless familair with this circuit as it wrestled with this fan over the summer, some mud dawbers built a nest on the fan and it burnt up trying to turn, blowing the fuse and my ATC unit.)

As Forrest Gump said "stupid is as stupid does".

 

Always tempting to go 99-02 if you have to do an ECM swap. They are also much less sensitive to other things like low temp thermostats and I have one with 4 non-functional 02's that runs just fine. I can't speak to your emissions testing issue, I moved away from Texas in 94 and have not lived there since (although frequently tempted to move back).

 

Long time lurker and first time poster; but I've recently battled that same list of 14+ codes, specifically the 0102 and 0135 codes. I found a random thread that suggested replacing fuse 2 under the hood, which controls all of those circuits. A simple fuse replacement resolved all 14 of those codes for me and it drove great for 2 days, until the CEL came back with 0135 and 0155 only. I'm suspecting a wire harness short somewhere on the O2 sensor wiring.
Simple #2 fuse swap may answer a lot of questions before you go through the whole swap process.