355 Few codes, headache

Not the easiest thing to do. You'd have to backprobe the ECU plug wiring and partially remove the backshell on the Motronic ECU plug with the ignition turned on.

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Not easy to do and yet I have done it several times....

 

Ok first of all I really appreciate the help I am receiving, without it I’d be pretty lost.

Id also like to point out, as I previously hinted at, fault finding electronics isn’t something I have experience with, in fact I bought a multimeter specifically for this latest issue and is my first time using one, i was able to do the resistance and power testing on the 02 sensors and fuses the other day, but breaking into ECU plugs is perhaps a little risky for me, unless it sounds worse than it is?

 

Just so there’s no doubt, the P1449, I thought this was the drivers side, bank 2, so the drivers side on a left hand drive car, so the ECU on its own in the upper engine bay?

By RH I’m assuming you mean right hand which would be the passenger side on my car?

 

Bank 2 is left side of the car.
Bank 1 is right side of the car.

They don't designate fault code with passenger or driver side.

 

So 1449 is the ECU on the left then, thanks

I’ve left the battery disconnected overnight, when I get home I’ll let the car idle and see what Happens with the light.

i may spray some electrical contact cleaner in the 4 pin plugs on the Cat ECU

I’ll then drive the car and see if I go into limp mode aswell as obtain fresh codes.

So my take on this is, if I do the ECU relearn, contact clean the 4 pin plug, and the SDL still doesn’t go away followed by limp mode, then providing codes 1445 + 1448 don’t appear the issue has to be wiring no? Because I wouldn’t have thought an actual issue with the cat itself would cause the SDL to come on a cold engine?

 

Pretty sure 1691 is CEL bulb missing.

 

Ok so I cleared the codes again, done the ECU relearn and let it idle for 15 minutes, the SDL has now gone off.

I did another code read and the codes I’m getting are

1447
1691
1452

so it’s dropped the 1449.

shortly I will take the car out for a run and see what occurs, or hopefully doesn’t occur…

 

The bulb was missing up bill a few weeks ago, I’ve cleared the codes multiple times since then so if it is related to the CEL I’m unsure as to why it’s on

 

So the bulb is in its socket and you are getting 1691?
Must be an issue with wiring to the bulb. Regardless,
1691 is a not a "problem" since it is only related to the bulb.

 

OK, so it seems your SDL issue is solved. You now have an Evap leak (1447) and a Secondary air issue (1452).

Let's look at 1447. Did you find any broken hoses at the gas tank evaporative hoses, or near the charcoal canister?

 

yes, the Check engine light works and has done ever since I installed the bulb, I don’t know specifically why the previous owner removed it, perhaps something to do with the sports cats (which I don’t realise my car had until page 1)

 

so as a full update, I was out in the car for 1 hour 15 minutes, no limp mode which is a relief.

however, bearing in mind I had the car idling for 15 minutes, then switched off for 15 minutes before I went out in it, after around 5 minutes the SDL began blinking, it went off by itself around 10 minutes later, it tried to blink a couple of times again very quickly during the road test, but other than this the SDL was off.

fresh code list attached, I see the 1449 is back?


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Sorry, got my left mixed up with my right.

Did you swap over the plugs on the thermocouple ECUs? I’m not sure what caused the codes to disappear. A plug swap, an OBD scanner reset, a battery reset and/or an engine run….
I’m worried that some of your codes will return if you go for a “spirited drive”.

When you were working on the thermocouple ECUs, did you accidentally dislodge some rubber hoses behind the bumper?

By the way, you can’t do a relearn on a 5.2. You need an SD1 tool.

(EDIT) Sorry, cross posted

 

I haven’t yet investigated this, will report back

 

no I didn’t get round to swapping any plugs or spraying contact cleaner on the 4 pin plug on the bank 2 ECU (1449)
This was because the SDL went off during the idle, otherwise I would have done.

im not 100% sure yet if my SDL issue has gone away, as you can see from my update above and the code attachment, From what I can gather on my research over the last few days/weeks the SDL is very temperamental on these cars, so I’m not sure what to make of it?

my test drive did have some brief doses of spirit too.

regarding rubber hoses, is there anything specific I should be looking over? It was quite a task replacing those 2 ecus as there was plenty of cables in the area, nothing caught my attention at the time. Would have been a lot easier with the rear wheel removed and the inner arch

 

OK. I wouldn't confuse the issue by swapping them now. Your situation seems to have improved a little.

Here are some of the hoses in that area.

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It might just be a loose junction

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P1117 Is your O2 heater again (RH bank, upstream), not as suggested by your code reader (coolant temp sensor).

P1447 I don't have this on my list, but it's in the cat temperature section of the code listings.

P1691 Lamp circuit?

P1451 This is related to an electrical short to ground in the secondary air solenoid valve circuit (at least on the 360). On the F355, the Motronic ECU doesn't control the solenoid valve directly, but rather the secondary air relay in the passenger footwell. This is one of those codes which leads to lots of wiring checks with inconclusive results. You may want to search the forum for ideas, using P1451 or 1451 as searchwords

P1449 Bank 2 cat temperature. Might be a good time to break out the voltmeter/ohmmeter as previously suggested. My only concern is the intermittency of the problem. Checks may prove fruitless.

P0140 Dead O2 sensor RH bank, downstream.

P1448 Exhaust bypass again. I did suggest not swapping the plugs, but desperate times need desperate measures.

 

The actual wording of the code is
"Secondary Air Pump Circuit" (short to ground)

The F355 ECU has no way of detecting electrical short circuits on the actual pump wiring or on the Secondary Air solenoid valve wiring. The code may be completely different for the F355 or the actual F355 fault code description relates to a short on the Secondary Air relay coil circuit. This is relatively easy to check with an ohmmeter, but if there is a short to ground on the relay coil circuit, it's unlikely the Secondary Air pump would be running (when engine idling and cold) or that the secondary air valve would open. The relay controls both the pump and the solenoid valve for the secondary air valve operation.

 

The secondary air injection system on the 355 problems are:

Air pump frozen
Fuse at the foot well
Vacuum lines broken at the vacuum tomato can, or leading to the switch
Maybe broken wires at the 2 pin connector

It's rarely the car ECU.

 

It appears my SDL and limp mode issue is becoming an issue again.

To re jog memories my car has three cat ECU’s, I replaced all three ECU’s back in February and 2 thermocouples, the left cat and right cat, the bypass valve thermocouple is the only thing I didn’t replace, my car has a tubi exhaust and aftermarket cats

When I replaced these and cleared the codes I found the SDL was still flashing upon start up but no limp mode, at the time I was still getting the codes 1449 and 1448.
a fresh code read recently reveals these two codes are still active after being cleared.

now I can hear the exhaust note change when driving enthusiastically so I doubt the valve is stuck one way of the other, so I’m going to replace the thermocouple for the bypass valve which arrives today/tommorow, although can this cause the limp? My understanding from reading threads is this causes a check engine light and has nothing to do with the SDL? Although there appears to be some confusion.


By the way, how easy is it to access the valve to replace the thermocouple? I had a brief look and i appear to have a cover over the top of the bypass valve, there was 3 nuts securing this cover but once undone didn’t seem to offer much scope in removing the cover, does the rear bumper need to come off?

 

For the left bank code, there's not much else to check other than the wiring to the ECU.

Check for 12 volts on the green wire (key on), a good earth on the black wire and check continuity from the purple wire to pin 14 on the ECU.

Not sure about the bumper.

 

The bypass valve malfunction can cause a SDL.

To access the bypass valve thermocouple
1) remove both air filter boxes
2) remove MAF and the hoses leading to the MAF
3) remove the heat shield over the muffler

Access to the thermocouple is now possible.

 

So I’ve changed the bypass thermocouple (thanks @yelcab for the info)

upon doing so I noticed this pipe has a hole where the jubilee clip was, not sure if this could be contributing to the code 1448.


and as for code 1449, the bank 2 left hand side cat ECU, upon inspecting the 4 pin plug I noticed the cream cable had a break in the sheathing, also the green cable had some insulation tape wrapped around it, after taking this off the green cable is as shown, so this definitely needs attention
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Those pins and cables for the Thermal Couple Unit need to be replaced. The control unit might need to have its pins cleaned as well. That looks like serious corrosion.