355 Codes 1448, 1451 & 0410

Code 1451: Not sure I understand the code.

Secondary Air Pump Circuit
"short to B+
Not present"

What is not present? The short to B+???

The only electrical relationship that the Motronic ECU has with the circuit is the solenoid of relay "L" (on the 5.2 car). The message, therefore, seems to be saying the relay coil is shorted or there is a short to power between the relay coil and the ECU. Can you hear the pump running with the engine warming up? It's not easy when the engine is running. The relay coil doesn't have a fuse. The relay has a double pole, so you can't really swap it with anything (unless relay F in the luggage compartment is the same type/power)

Code 0410: I don't see that on my list. What does your scanner say for this? It may not be applicable to the 355.

Code 1448: could be anything related to the bypass valve.

There may or may not be a relationship between 1451 and 1448 as I earlier suspected (given the definition of 1451 being something specifically electric).

What format is your photo? Just drag an image file (jpg or similar) from your computer with your mouse and drop into the message area. Decide where you want the photo in the message and click on FULL IMAGE next to the thumbnail of the file (below the message area/text box)

 

Sorry, missed this comment. Can you jump the relay to start the air pump? i.e. sockets 30 and 87. This will work with the ignition off (at least one of those pins will have live battery power on it).

 

The fact that you have two codes related to vacuum driven devices emanating from the rear passenger side hose mess leads me to think you should check out the vacuum switches, vacuum cannister, vacuum lines in that area.

If everything there checks out, come back for more.

 

P1448 i get whenever i wire my exhaust valve open..no way to avoid it i guess on the 5.2 so that code you're probably getting just related to the valve malfunction

 

The first picture shows ohms, not volts.

The second picture shows only half the volts are getting to the air pump (unless there is something wrong with your measuring method)*.

I'm not sure of the logic for activating the pump. i.e. does the car need to be running for the ECU to command the air pump on? Also, was the engine warm? The pump will only operate during the warm up cycle.

Unfortunately, my car is in a workshop, so I can't compare my readings with yours.

*

As I was reminded recently, voltage measurements should be taken across a resistance. There is very little resistance in your circuit (just the wiring from the battery and the wiring through the chassis back to the battery). In most cases, however, I've found that quality digital multimeters are pretty good at measuring these things.

 

I posted this image for you in PM a few days ago...



No air is supposed to be coming out of the cutoff valve from that port in your video. Vacuum is supposed to be applied to that port from the secondary air solenoid valve.

Did you check the (electrical plugs on the solenoid valves) to see if they had been accidentally swapped (as I asked)?

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Is this on startup or with power going directly to the pump?

 

Yes, if the engine is cold, the air should flow through the valve.

It's awkward to access these components, but can you pull off the vacuum hose going to the secondary solenoid valve to see if you are getting a vacuum with the engine running? That's the hose at the bottom of the valve.

I think I know what's happening with your photos. They are about 5 times larger than they should be. Here's a resized one.

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Or maybe not. Your relay jump photo was the right size.

The quality is strangely poor, however. Perhaps insufficient light. I tried to fix it, but with little success.

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If you have proper vacuum, I would recommend swapping the solenoid valves to see if the secondary air starts working, but at this point, we don't know if you exhaust bypass valve solenoid works.

Can you possibly get your ohmmeter leads on the pins on the solenoid valve to see if the coil resistance is correct (around 55 ohms).

It's probably ok unless the wiring is faulty. It uses the same signal as the secondary air pump.

 

I suppose an easier way of checking that the solenoid is functioning is simply by checking for vacuum on the pipe going to the secondary air shutoff valve with the engine running (car cold). Much easier to access.

With the car warmed up, the vacuum should disappear.

 

You are making this too complicated.

Test 1: Apply 12V to the pump from a battery. If it runs, it's good.
Test 2: Is there vacuum from the accumulator to the input of the switch when the engine is idling, and holding when you turn off the engine? If yes, vacuum is good.
Test 3: Apply 12 volt across the switch controlling vacuum to the valve, is there vacuum now at the input to the one way valve? If yes, the switch is working.
Test 4: Apply 12 to the switch and the pump from the battery, is there air flow to the headers? If yes, all control devices are good. If not, the valve is bad.
Test 5: Remove the two check valves at the exhaust manifolds. Blow through them in the direction of flow. They should flow. Blow through them in the other direction, they should not flow.

if all that is good and you still get the CEL, your ECU is bad, or the pin from the ECU to the connector of the switch is bad.

 

That's why I suggested checking the vacuum directly at the shutoff valve, Mitch. The lower components are hard to get to. This avoids step 2 and 3. Step 1 has already been done.

For reference, Volvo or aftermarket Volvo check valves provide an alternative to the extremely expensive Ferrari versions.

https://www.ferrarichat.com/forum/posts/147903982/

I picked one up for U$12

 

Don't get me started on previous work done by previous mechanics.

 

Good luck.

That still doesn't explain this...