Hello Folks,,

My 04 VDP has rough idling and the message (Restricted Performance) pops up. This usually happens upon warm start. So in the morning I would do the cold start and everything is fine and I would drive the car for about 1-2 hours, everything is fine. After I park the vehicle for about 10-30 minutes and start it again it starts but idles roughly and the message pops up. The rough idling continues for about 30 seconds and then goes away but the message still appears.

In the beginning I thought it was plugs or coils but when I took it to (Advance Auto parts) I had a guy from there scan it and I was told it is an O2 sensor.
There was another code that I don't remember (I will post it later) but the scanner couldn't read it. The guy told me it was a Jag specific code you might need Jag specific scanner to read that code.

Anyways was wondering if anyone here had the same problem and what they did about it.


Please any input helps,,

Best
Sam

 

Best to post the codes so people aren't guessing. Even better spend about $10 and get your own OBD tool with live data like elm327. (You're likely to need fuel trims.)

 

Hi Sam,

+1 on the importance of posting the actual fault codes here so we're not guessing.

If the engine runs rough as soon as it starts then an O2 sensor (O2S) or its electrical circuit is probably not the only problem. The Engine Control Module (ECM) does not even refer to the O2S signals until they've had time to warm up, typically 20-30 seconds. Until the sensor heaters warm up, the ECM uses a predetermined fueling map which is selected based on inputs from other sensors like the Mass Air Flow Sensor (MAFS) and Engine Coolant Temperature Sensor (ECTS).

JagV8's recommendation of acquiring your own OBDII scanner with live data is good advice, especially in order to be able to read live data and fuel trims, which can tell you if something is amiss such as an intake air leak causing a lean air-fuel mixture that the ECM cannot correct.

It may also be important to know which proprietary Jaguar fault codes have been triggered, which will require having the car scanned by a Jaguar dealer or an independent shop with the right equipment to read the Jaguar B, C and U codes.

For an idea of the types of malfunctions that can trigger the Restricted Performance mode, have a look at the DTC Summaries manual. Any code that causes the maxium engine rpm to be limited or the transmission to go into Limp Home Mode will also trigger the Restricted Performance warning. You can download the DTC Summaries manual here:

X350 DTC Summaries Manual

Cheers,

Don

 

What Kind of tool is that and where can I get it? I mean $10 is nothing lol

 

Sorry I forgot to post the codes earlier,,

Here are the codes,,

P0171 O2 sensor (it also said bank 1 lean)

P1111 This is the code the (Advance Auto Parts) scanner could not read

 

P0171 is often an air leak and does not appear to be an o2 sensor.

I looked it up in Don's link and i thought it sounded familiar.

I suggest you search for air leaks in ducting prior to the TB.

 

P1111 is a good readiness monitor code and can be ignored.

Here's the explanation of P0171 from the DTC Summaries manual for which I provided the link in my previous post:




Look at the "Possible Causes" in the right column and focus on the ones that can affect one cylinder bank only. For example, low fuel pressure will affect both banks, so you would probably also have P0174 triggered for bank 2. Since you only have P0171, look for causes that can affect one bank only. Air leaks between the MAFS and throttle body generally affect both banks, but there are air leaks that affect one bank only.

Cheers,

Don

 

I have a question about the OBD II live data tool. Can it read the proprietary codes?

 

Most OBDII scanners can read only the Powertrain (P-prefix) codes and certain CAN protocols mandated by law. Manufacturers can implement additional diagnostic trouble codes, and in Jaguar's case they take the form of Body (B), Chassis (C) and Network (U) codes, which cannot be read by most OBDII scanners.

To read those proprietary Jaguar codes requires a dealer-level diagnostic system such as IDS, WDS or SDD; a third-party system like Autoenginuity with the Jaguar enhancement; or a dedicated handheld unit like the iCarsoft i930 Jaguar edition (the only Jaguar-specific handheld I know of, but it has received mixed reviews on this forum).

Live Data refers to the capability of many OBDII scanners to read the signals from some or all of the vehicle's sensors and operating parameters, such as oxygen sensor voltage/current, engine coolant temperature, engine rpm, Short-Term Fuel Trims (STFT) and Long-Term Fuel Trims (LTFT), etc.

Cheers,

Don

 

Thank you Don for the explanation and continued help.

 

Live data will also let you see if it happens to be close to a P0174 i.e. whether both banks are lean.

Some software can tell you the freeze frame data for each code and again that will show what the other bank was like when the code flagged.

 

Update

So I have found that the tube between the air intake box and the throttle was disconnected over on the box side. Fixed that cleared the codes and drove it for couple of days. Problem appeared again after a warm start up. Starts rough but then clears after 30 seconds of idling.

However, it now (when the restricted performance message is on) hesitates under mid-high throttle applications. If I apply more than 60%-90% throttle it jerks and hesitates and it feels like it is not delivering fuel. I am now thinking it is either Fuel filter, fuel pump, or fuel injectors. What do you guys think? Also do you think the throttle body has got to do with anything? I don't think it would be the plugs or coils because it drives and idles normal under normal driving conditions


Waiting for your help folks

 

You have found the air leak so I suggest you read the codes again and report back.

The root cause could be the TPS but get the codes first.

 

Look at fuel trims too.

 

my vehicle now has 167000 miles...I am wondering if it is the fuel pump...anyone knows how long those pumps go for roughly before they quit working?

Thanks

 

Sam,
You continue to ask for help, yet you still have not included the year, model, such as;
04/XJ8 ---in your signature block.

 

sorry about that my vehicle is a 2004 Vanden PLAS 4.2 V8

I did put it but did not appear on my signature

 

Sounds a lot like a problem I'm facing now & initially thought same as you - turns out my coolant was leaking into my transmission- needing to overhaul my gearbox for 2005 super v8 now as some plates damaged.

 

Just in case you missed it, when you add the information in the Edit Signature window below the signature preview window, scroll even farther down to find the Save Changes button and click that before you exit your Control Panel.

Cheers,

Don

 

What about the new codes. There is little value in asking people to guess. DTC's lead you in a specific direction.

To get the most out of this forum and also to help other future readers, provide the detailed codes as Meirion suggested.