My 2006 Super V8 developed a head gasket leak that pressurizes the cooling system and blows coolant from under the 20 PSI cap and tends to back off the top radiator hose so it has been in my garage for the last 6 months with a battery maintainer on it. I recently moved it out to clean the garage and now the little oil can light stays on. I am using Castrol Edge 0W-40 full synthetic and the oil level was above the minimum hole on the dipstick. I put in a partial quart I had in the boot and the level is now above the mid point but the oil can light stays on.

Today I checked the OBDII with my Icarsoft I930 reader with the ignition on and engine off and there were no engine codes (DTCs) set. I checked the jag codes and it had several “battery voltage out of range” codes in various modules and the Powertrain Control had a P050B (cold start ignition timing fault) and P023B (SC coolant pump circuit low – which it has had since I grounded the SC pump relay coil ground side because the ECU was not grounding it) but there were no other faults that related to oil pressure. I started the engine and the little oil can light stayed on and the brake light stayed on. It had “Vehicle too Low” and “Light switch Off” messages. I shifted it with foot-on-brake through R N D N R P and the brake light went off and stayed off but the oil can light remained. After initial idle at 1000 RPM it began to oscillate between 600 and 800 RPM at idle and when I tapped the gas peddle again it died. I restarted and the oil light stayed on, the brake light was off, and the “Vehicle Too Low” message did not come up but it again began to surge between 600 and 800 RPM so I turned it off again.

Is there a way to check the oil pressure sender other than just replacing it? Or a way to check oil pressure with my I930? I suspect the engine needs a good run after all the idle time, but I can't chance it until I know if it has adequate oil pressure. It sounds OK at idle and ran well enough to drive it from the lower garage to an upper driveway, but I sure don't want to cause it more harm than it has already experienced with the head gasket situation.

 

The only real way to test actual oil pressure is to remove either the oil pressure switch or the oil temp sensor and use an adapter and gauge.

bob

 

Do not drive the vehicle with the oil light on.

 

the 350 manual says:
Oil Pressure Switch Installed at the right front of the structural sump, the oil pressure switch connects a ground input to
the instrument cluster when oil pressure is present. This switch operates at a pressure of 0,15 to 0,41 bar (2.2 to 5.9 lbf.in2).

So is the oil pressure sensor a switch that is either open or closed to ground? Could a poor connection to the switch cause the oil can light to stay on? I never had it stay on before so perhaps some varmint chewed the wires or high humidity in my garage caused a poor connection?

Anyone have a photo of the oil Pressure sensor location? The picture in the manual shows a pressure sensor and a temperature sensor together but does not say which is which. Should I be able to see it from the top or must it be accessed from underneath?

 

Had a chance to jack up the front today and the oil filter is right in the front with one sender unit right beside it and one above. The photos I find on line do not quite match so is the easily reached sender the pressure switch or the oil temperature sender? Anyone know what thread it has or what thread I would need to remove it and attach a pressure gage?

My filter with sender beside it




drawing from web


Drawing from 350 manual





adapter from web that says thread is M10X1/25

 

Found another sensor diagram for a 2004 that indicates that the lower unit I am seeing may be the oil temperature sender and the pressure switch is the one up higher and harder to reach (of course) . Can anyone verify?

 

Its #10 on your diagragm

 

Thanks, yes I read it that way too although my switch is in a different place to the left of (the car's left) and above the oil filter. I was able to remove the connector on the lower sensor and then could see that the upper one has only one wire in its connector so it is definitely the pressure switch. It is in a very tight location and hard to reach so I will try again tomorrow. If anyone knows what the thread spec is that would be a help if I need to remove it and connect a pressure gauge. I sure don't want to mess up the threads if it is not a normal NPT thread.

 

Possibly look at a wiring diagragm to better locate the oil pressure switch. Also, might be prudent to purchase and swap in a new oil pressure gauge.

I usually don't like throwing parts at an issue but this I would make an exception for since it's a hard location to get a mechanical gauge to...

 

I am sure the sensor with one wire to it is the pressure switch and I can see it well enough - it's just in a tight space and if the adapter info is correct it has a metric thread that my pressure gauge set probably doesn't have. The adapter may be a good idea even if I don't add an oil pressure gauge in the cabin as it would allow me to use a normal NPT thread gauge to check oil pressure and then just plug the NPT hole.

Here is a better photo of both sensors - the pressure switch is the one higher up with the connector still attached. It is a tight space to get a hand in.



My current thought is to make sure the switch body is grounded and to get the connector off and try cleaning it with contact spray and reattach to see if it then works and if not to remove the pressure switch and test it to see if it is switching under pressure. It seems more likely that the switch is the problem rather than the oil pump itself since oil pressure was fine when parked in the garage and then after 6 months not OK, but stranger things have happened.

 

UPDATE:
I checked the continuity between body of the pressure switch and ground on the engine oil pan and it is grounded. I checked for continuity between the pin on the switch and ground since the description in the manual says it “connects a ground input to the instrument cluster when oil pressure is present”. The pin on the switch is grounded, so it appears to work opposite to the description and opens with oil pressure. I left the oil switch and oil temperature sender disconnected and turned on the ignition. There was no oil can light but the check engine light was on. I connected my i930 on OBDII and there were two listings, ECU1($FD00) and ECU2($FD20). The first one had P050B-Cold start ignition timing performance, P023B-Inter Cooler coolant pump circuit low, P0198-engine oil temp sensor high. The P0198 was pending and the other two were both current and pending. I erased the codes and the P0198 and P023B remained and the check engine light remained and flashed for a bit. The second one had no DTCs. There was also the usual “check pressure spare tire” message (no sender in the spare) but no “vehicle too low" because the front wheels are off the ground. I checked the i930 for any oil pressure data streaming choices and there are none for oil pressure or temperature.

I connected a clip lead between the pressure switch pin and the connector and turned on the ignition and the oil can light came on again and if I disconnected the clip lead with the ignition still on the oil can light went out so either the switch is not opening with oil pressure or there is no oil pressure. I'll have to remove the switch and try testing it and/or put a pressure gauge on the block where it screws in. I do have some metric adapters in my fuel pressure testing kit but no M10X1.25; the closest is M10X1.0.

The oil pressure adapter site says it fits (2006 and earlier only) But the ÜRO PARTS C2S42616 switch ($28 at RockAuto) says it fits 2004 to 2009. The RockAuto photo does not show the pin end but a photo of this part on eBay appears to show two pins in the switch but my connector has just one wire and my switch has one pin. RockAuto has other pressure switches that do show one pin. I emailed the adapter maker with my VIN and asked if his adapter fit my car and got a call back from Steve who said he looked up the switch for a 2006 SV8 and it is a different part number than the switch for which he designed his adapter so he could not say for sure if it would fit. So...now to pull the switch and try to test it and try to determine what the thread actually is.

Adapter for pressure switch to add a pressure gauge:
Jaguar V8 Oil Pressure Adapter - TheJagWrangler

UPDATE 2
I managed to get the switch off and its thread was a close match to an adapter in my oil pressure gauge set so I got the gauge hose installed in the switch hole and had 60 PSI oil pressure at cold idle. Whew! BTW, if anyone else needs to remove this pressure switch, I used a 21mm deep socket and ratchet to loosen it and back it out one click at a time Some oil drains when it comes out but not a lot so you don't need to drain the oil from the pan first - just have a pan under the switch. Now to find a new switch.



.

 

That's good news. A new switch should remedy this issue.