Peugeot 406 Coupe 3.0 V6 Questions

[Shpetan]

Sup everyone.

Im very interested in buying a 406 Coupe 3.0 V6 and the one thats out there is pretty much in mint condition. Only done 160k kms. Seller states that hes changed the trans oil twice which is not bad in my eyes. My only concern is how good the price is alongside sellers eagerness to wanting to sell it to me rather than the guy coming from much further away from where hes living.

The 406 to my knowledge is equipped with ZF 4HP20 Auto transmission. Works just fine except theres one issue from time to time only. Sellers description of the issue when putting in reverse is: "It's not the engine light that starts to come on, it's the sport and winter modes that start to flash. I talked to a mechanic who said that the most likely thing was the engine mounts and I was going to change them but forgot to order them but it's a fairly easy fix as they are very accessible, at least the upper ones! If you put in regular drive and go between drive and neutral they go out again so as I said you can drive with them like that and it happens quite rarely or you can fix it"

How true is that this might be the exakt issue? Could it be that it isnt related to any of that but that the transmission is finally starting to give up slightly due to wear? Ive read that the ZF 4HP20 isnt exactly the most reliable. But ive also seen 406 Coupes in other countries that have done much more and thats not even including Germany.

[ozfrog]

I’m sure that someone will correct me if I’m wrong, but my memory is that those two lights flashing is on the AL4 transmission, not the ZF.

If I’m right, then that’s why buyers in Australia - it’s where I live and the only market that I have any knowledge of - if they were looking for a used Peugeot automatic, they would always prefer one with the ZF transmission, not the AL4.

The AL4 transmission is okay, if you like automatic transmissions. It’s not the most modern thing around, and it doesn’t have as many gears as a modern transmission does. And it has this problem with the solenoids inside the transmission. That’s what the two lights flashing is telling you.

The first 306 cabriolet I owned had the two flashing lights and at the time, I didn’t know what they meant. What I figured out was that the flashing lights would come on only when the engine or transmission was cold and I tried accelerating too fast. Once the engine had warmed up to operating temperature, I would never see those two lights. If I let the engine cool and then start driving again, I would have the same problem.

That was a great little car - until the engine was cooked because the previous owner had bypassed the leaking heater core using a length of garden hose! And garden hose doesn’t hold the pressure needed for a hot engine when driving at 100 km/h or more for a couple of hours.

[xantia_v6]

The ZF 4HP20 was.the only 4 speed transmission fitted with the ES9 V6 engine, the AL4 would not take the torque.

The flashing sport and snow lights indicate that the transmission ECU is unhappy about something, but not unhappy enough to go into limp mode. There may be stored error codes in the ECU. My first suspicion would be the selector switch mounted on the side of the transmission.

[Kees]

My experience with the V6/3.0 and the 4HP20 i had 3 of them, all broke down around 250.000 Km.

[ozfrog]

The ZF 4HP20 was.the only 4 speed transmission fitted with the ES9 V6 engine, the AL4 would not take the torque.

Sorry. I wasn’t meaning to imply that the AL4 had been fitted to the 406 with the V6 engine.

My comment was more about the flashing lights. But I wasn’t aware that the flashing lights were used as a standard for indicating that there was a fault with the transmission.

[PaulC5]

If only the engine mountings and is low cost to fix then insist the seller does this before you consider buying the car. Then you will know if the fault has gone. If the seller will not fix then you know it is something expensive.

[MattBLancs]

As others have said, flashing sport and snow lights is Auto gearbox ECU isn't happy. Sadly the flashes don't have any more meaning (i.e. not count the flashes and translates to what's wrong)

To be honest I'm not sure how failing engine gearbox mounts could trigger those to illuminate??

There's effectively four mounts on a 406:
Top of the gearbox (whether auto of manual it's in same spot, though is a slightly different mount though) access from above by removing air filter housing.

Top of engine: effectively two things here, a "rubber donut" and above it a torque reaction arm with a round bush either end. Donut has a hard life on a V6 (is my understanding, no direct experience)

Underneath there's another torque reaction mount built into the long driveshaft engine bracket.

All are pretty accessible and straight forward to change.
But as above, I don't understand how they'd cause the symptoms described! (More often clunks on/off the power)

[xantia_v6]

A bit more explanation about the selector switch:

The gear selector has 7 positions but the switch has 13 positions so that the ECU can detect that the lever is half way between 2 positions, which is one cause of the flashing snow and sports lights. Transmission overheating is another possible cause. A diagnostic tool should show that the switch output code matches the actual position of the lever.

[Shpetan]

A bit more explanation about the selector switch:

The gear selector has 7 positions but the switch has 13 positions so that the ECU can detect that the lever is half way between 2 positions, which is one cause of the flashing snow and sports lights. Transmission overheating is another possible cause. A diagnostic tool should show that the switch output code matches the actual position of the lever.

Read the above too and thats very interesting. The seller is very avoidant when the issue is brought surrounding the switch. And his eagerness on wanting to sell it to me right now isnt helping so ill pass on it. Great insight gained when it comes to this kinda issue. I doubt it would have been too much work on it but given the list i havent listed that hes worked on replacing plus no documentation from before.. Yeah. Skipping.