Hello everyone, I have a Jaguar X-Type 2.5L V6 2002, with Some problems: every time when the car is cold, the car drives and feels like it runs on 4/5 cilinders. It feels normal as Soon as the car hits 90 degrees. Also when cold started I have no brake boost. I suspect the hose or the vacuum valve. I would replace the O2 sensor, but I have read that many times the sensors are okay but there is something else going wrong. My fuses are fine. Anyone got an idea?

 

So, no fault codex thrown? Or, no engine light?

 

P0037 is a diagnostic trouble code (DTC) indicating a low voltage condition in the heater control circuit of the downstream heated oxygen sensor (HO2S) on Bank 1 (passenger side) in Jaguar vehicles, particularly the X-Type and S-Type models.

P1646 is a Jaguar-specific OBD-II diagnostic trouble code indicating a malfunction in the HO2 (heated oxygen) sensor control for Bank 1, upstream — the sensor located before the catalytic converter on the engine's primary bank. P1647 is an OBD-II diagnostic trouble code indicating a HO2 (Heated Oxygen) Sensor Control Malfunction on Bank 2 Upstream in Jaguar vehicles.

• Location: The upstream sensor for Bank 2 is typically located on the left side (driver's side for LHD vehicles), often near the front exhaust manifold or catalytic converter.
  

So that's one possibility of the source of your problems. But those codes sometimes do stand for something else...

 

is this a real post or a post made by ai ?
sounds kinda funky written
an 02 sensor to fix no brake boost?
exactly which fuse numbers did you check?, can you please list which fuses you suspected?

 

Yea its real but my first language aint english, that propably why it could sound funky.

Ill break it down to you:

I have 2 problems, both when the engine is cold.

1: I have no brake assistence untill i drive like 100 meters (300ft), i suspect that the brake vacuum valve is broken or that the seal isn't what it used to be again, but some people say that when the seal leaks, it could cause the engine to feel like it runs on 5 cilinders when cold.

2: The engine feels like it runs on 4/5 cilinders, only when the engine is completly cold. but as soon as it is fully warmed up, the engine feels normal again. So for this reason i suspect the 02 Sensors. Because maybe the warming up element of the 02 sensors is broken. The only thing is that a lot of people say on this site or other sites that the 02 sensors are fine most of the time. So could it be a common ground?

I checked F38 & F42. I think R7 should be fine, and i dont know how to check if it is fine or not. (I think that there would be more problems with the car if R7 was broken.)
There is 1 engine light on the dashboard.

When the car is warmed up, it drives and feels good.

 

Thanks, i figured it had to do with the O2 sensor, but do you know what could be the problem? It seems weird to me that both HO2 sensors would be bad at the same time

 

Fix any vacuum leaks then see which codes occur, if any.

 

.
+1^^^
Try the vac line grommet in booster.
As they age and become brittle, often fall to bits or just so loose, the plug connector falls out.

Result?
No brake boost and significant vacuum leak.

Good news?
Cheap as chips at your local auto retailer as they are purely generic (albeit available in 2 sizes).

Cheers and best wishes.

 

> It seems weird to me that both HO2 sensors would be bad at the same time.

Well, I reckon a problem of the O2 sensors could e.g. be that they are simply dirty and want to be cleaned - and it would make perfect sense, that they are dirty at the same time - after all all the O2 sensors are always going along for each ride, and none of the O2 sensors ever stays home throwing a sicky or a party or a party while throwing a sicky..

 

Once you have air leaks you _may_ have some false codes, so it's always worth fixing any leaks.

If you then have codes, say both O2s, do the usual checks - fuses/relays/wiring before swapping in replacement(s). Be sure to get the right new ones, don't buy any cheap rubbish or you'll be doing it all again.

 

I have ordered the right o2 sensor, it will come in next week, ill let you guys know

 

Hey Jhonny, did you find any air leaks? If so, where?

Cheers.

 

I think the vacuumvalve for the brake line (brake booster), I ordered the valve and when it comes in ill update you. Will probably come in next wednesday.

 

I think you have mutliple unrelated problems. The 02 codes should not impact brake booster functionaility.

FYI, I have ALWAYS had these exact same DTC codes reported (same as yours but also 57 Heated Oxygen sensor bank 2 heater control circuit low).

37, 57, 1646, 1647

The car runs absolutely fine...hot/cold starts, running, idle, fuel consumption. perfect. Fuel consumption is a stable 10-12 km per litre.

But have always had the codes ever since I put a code reader on 4 years ago. No dash warnings. Codes return immediately if cleared.
I ran through the Service Manual procedure for checking/testing wiring/fuses/ resistors but never got to the bottom of it.

So your cold start issues could be the brake vacuum line and also could be a leaking intake gasket. V6 also prone to water collecting in spark plug wells and also oil. That has caused me rough idling in past.

Given the cost of 02 sensors, and not seeing any performance issues whatsoever, I'll just live with it. I don't think a sensor clean wiill work if the heater element is indeed burnt out.

 

Ah, but Alec, the reverse is entirely possible.
The rubber grommet is a known leakage and failure issue.
Moreover, Jhonny has inspected his and sufficiently concerned to replace it.

The last time I looked, the cost of O2 sensors was many multiples the cost of a generic brake booster grommet (they come in only 2 sizes and are cheap as chips at local auto shop). Not denigrating your similar issues of codes, but fixing vac leaks is a necessary starting point. Other possible leakage points include corrugated section at MAF or inlet manifolds. In fault identification, I like a logical progression . . . solve one issue before tackling the next.

Cheers and best wishes,

 

I think I hadn;t made myself clear. I entirely agree with you.

I was referring to my identical situation (re DTC codes) that I have decided to not replace sensors.

My other point made for the OP is they are likely looking at multiple issues and the DTC codes have nothing to do with the brake booster issues.

OP should certainly inspect/replace relevant seals or hoses causing the brake booster issue. But also to consider the rough running is due to intake side gaskets, water and/or oil weepage into the spark plug wells.

So, ignore the DTC's for now, focus on the air leaks and the contaminated spark plug insulation issues. These entirely explain the symptoms, not the DTC codes.

 

Those codes mean it can't fuel exactly right, so it will run rich because lean destroys engines.

Rich gradually destroys cats (and wastes fuel).

 

Hello again,

I put in a new brake boost valve, and also a new HO2 sensor. Both were not the problem.

So i still have the same problem, when the car is cold the engine runs on like 4 cilinders and also the brake boost kicks in when its warmed up.
Does anyone have any tips? Or a obd2 scanner which can read jaguar x type's? I tried with a obd2 scanner from a friend, but that one cant find my jag.

 

So does that mean that the spark plugs are bad or that the there isnt enough air in the cilinders?

 

Have you fixed aur leaks? After that what codes do you have?

People keep saying & asking the same because you don't make clear if you have.