P1602 and P0040

Swedish Paul

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1,807
Maybe it’s coincidence, but i refilled with 95 octane fuel and after 15/20 mins running, I got the Slow Down warning at 60mph after some hard acceleration. The engine felt like it was misfiring, but I only got a P1602 code. I reset the code and now have a P0040 code. Did a battery reset and it didn’t help. Any ideas?
 

CatmanV2

Member
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48,547
I wonder if that's Maserati specific but the general code would indicate that your lambda sensors have been switched

  • The connectors for bank 1 sensor 1 and bank 2 sensor 1 have been swapped
  • Crossed oxygen sensor wiring
  • ECU failure
  • Open or short in oxygen sensor wiring for bank 1 sensors

My money is on the last which would possibly account for all your other issues. Just hope it's not a duff ECU but you probably want to get this sorted.

P1602 is just where you've disconnected the battery. Did you check for pending codes before resetting the P1602?

C
 

Swedish Paul

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1,807
There were no other codes. I can’t see how it can be swapped sensors or wires as nothing has been changed. I will try another full reset in the morning and check the sensor connectors, make sure nothing has come loose. Otherwise it’s trailer time. And 500 km to the nearest dealer. Joy.
 

Swedish Paul

Member
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1,807
Tried again this morning. No error codes, which is odd, but the ODB reader reports "Open loop (due to system fault)" on both fuel systems. I thought these were closed loops. And no numbers for the short term fuel trims which I suppose is caused by the same issue. Could it be fuel?
 

CatmanV2

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48,547
They should be closed loops, but if your lambdas are wrong, it'll go open loop.....

I really doubt it's fuel

C
 

spn

Junior Member
Messages
88
If nothing else has changed, I'd blame the fuel, what type was it, were you previously running on a higher octane fuel?

I've always run my 4200 on 98/99 so have no experience of how the ECU retards the timing to deal with a lower octane. If the octane dropped by a large amount (bad fuel?) it may be that the ECU couldn't retard the timing properly causing det.

If it couldn't retard properly, it may have gone open loop (limp mode) and run rich to protect the engine?

I'd fill up with decent fuel (V-power), reset the car and see what happens.

Cheers,

Simon
 

spn

Junior Member
Messages
88
The cars are designed to run on 95 octane.

C
I'm sure they'll cope with much lower than 95 but that wasn't my point, I'm suggesting that the issue may be due to the ECU's reaction to a significant drop in octane number.

Could be entirely wrong but bad batches of fuel aren't unknown and it'd be a cheap fix if it is fuel.

Cheers,

Simon
 

TimR

Member
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2,656
Personally, I dont put anything but the best fuel (V-Power here in the UK ) in any of my bikes, T5 or 4200. ( Except my 2T 300 MX ) Unless Im really "forced" to by circumstances....
Parts of Europe pump 101 octane fuel on the forecourts..Italy especially. Im a little surprised to learn the 4200 runs 95 by design..but I say that not knowing what the comp ratio is. Im sure I read they should have 98 or better ?
 

CatmanV2

Member
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48,547
4200 Manual
Only use unleaded premium fuel with high octane number (R.O.N.) - no less than 95.
Tank capacity: about 84 liters, including a reserve of about 18 liters.

GT Manual
Only use lead-free gasoline with an octane number (R.O.N.) not lower than 95.


Octane and the fuel distribution network is often misunderstood, especially in the UK. But it's a discussion that will never reach resolution so <shrug>

C
 

TimR

Member
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2,656
Coincidence that one of my bikes starting to misfire and lose power just now. 1 of 2 cylinders not doing it..and popping and banging..Fresh fuel- problem solved..!:)
The bad fuel came from another bike that was gone bad. Ive just had the injectors sonically cleaned and rewired all the FI side, about to put it back together today ...I now think I could have enjoyed the track day I missed if only Id put fresh fuel ! ( I've cleared the tank of copious detritus that I thought was clogging the fuel pump sock.- to no effect. I found injector wiring that was badly deteriorating from heat exposure...not sure any of that would have solved my problem until the fuel, transferred to a good bike, appears to be suspect)
Two birds, one stone !
:cool:
 

TimR

Member
Messages
2,656
Can you get the fuel out via the filler cap or is from underneath?

Look, Im not familiar enough with these cars to know..My 4200 has its fuel tank sort of in ine with the filler cap and neck...but this doesnt mean there isnt an obstruction or tight bend...

I dont know...but for a few quid....you can try pump/syphon the tank with something like this..? You might need to add length to the piping...and dont get it stuck in the filler neck !! ;)

https://www.amazon.co.uk/Streetwize...coding=UTF8&psc=1&refRID=AQCQ9RBN0TTM2QWKE46W

Good luck !
 

miket

Member
Messages
647
How much fuel is in the tank?
Why not try to fill up with Shell V Power in an effort to raise the overall/average RON!
 

Swedish Paul

Member
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1,807
Ah. More error codes now. I get P0300, 301, 302, 303 which are misfires on all the same bank. I also get P2097 which is Fuel system too rich on bank one which is no surprise. I also get P1323 which I don't know what it is. Now it's odd that the misfires just started on one bank. Fuses? Relays? Any ideas?
 

CatmanV2

Member
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48,547
...lambda sensor.....

1323 is generic. Knock sensor 4 or coil 4 over voltage seem quite common.
C
 
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Swedish Paul

Member
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1,807
Just to update this thread, the misfire was caused by the variator sticking open at high revs and not returning to the zero position at tickover. The mechanic twisted the camshaft, heard a click and now all is back to normal. Probably will result in the variators being changed, but I will see how it runs.