I've recently had the engine replaced in my Jag. Ever since I’ve been plagued with intermittent warning lights. Mostly “Failsafe Engine Mode” w/amber priority and concurrent loss of cruise control, which clears after I turn the car off, but returns after 1-5 miles of operation. I’ve also seen the “Restricted Performance” warning and “Check Engine” icon but they also self-clear and are not a persistent. My original engine had “blown” at 88K miles due to a combination of operator error, ignorance, and bad luck. The replacement engine continues to run smoothly but I’ve notice a stronger, more astringent exhaust odor. My mechanic isn’t able to isolate the cause and advises I take it to a dealer. That’s going to be my final option, if I can’t figure this out myself (with a little help from this forum). I’m mechanically competent (maybe a 3-4 on this forum’s 1-5 scale) but not equipped for large/complex jobs. I'm also confused about why the warnings are not continuous? If the monitoring system detects a fault shouldn’t the ‘failed state” remain until either the problem is fixed or the computer memory is reset? I currently don’t own an on-board scanner but it appears that situation may not last much longer.

 

You need to get the OBD codes read. I'm guessing your technician did that. Ask him for it.

If you have check engine lights turned on you will have codes.

 

Before you hand it over to a dealer, together with your shirt and the keys to your house, invest in a cheap OBD2 scanner and get some hard data from any stored codes, at the very least it might tell you where to start looking.
For now try a "hard reset" via the battery (disconnect earth lead and touch it to +ve terminal for 30 seconds)......
Also assess the condition of the battery itself - a slightly duff battery will throw all sorts of spurious "faults" - again a $5 multimeter is a good investment.

 

Thanks guys. I just ordered a iCarsoft i930. My mechanic gave me codes P0175 (Bank 2 combustion too rich) and P1571 (Break switch malfunction). I'd gotten previous advice, from joesoap on this site, to check live data particularly fuel trims. I'm thinking I'll be able to figure out how to record/display that data once the OBD2 scanner arrives. I'll try the "hard" resets and check battery voltage as well. Thanks for the tips.

 

P0175 would tend towards the upstream O2 (lambda) sensor on (your) drivers side (bank 2)

 

OK I did a hard reset, checked battery (12.3Vdc disconnected, 12.2 connected, and 14.2 with engine running and warmed up). Took a test drive and got the failsafe message within less than 2 miles. Car started, warmed up, and drove with no other problems detected. Message cleared when I restarted the car. Guess I'll have to wait for the OBD to continue troubleshooting

 

The brake switch malfunction code will cause RP! Having to do with the failsafe redundant feature to disable cruise control- Remember the runaway Toyotas?

Check the archives and fix the brake switch. Then I agree with kyle. I would chart the Bank 2 fuel trims and sensor voltages with your new scanner and look for disagreement between pre and post cat lambdas on the bank 2 side. From that, you will get a good idea if it is the sensor or some actual engine problem causing rich on that bank alone.

 

Thanks Ross. RP=Rapid Propulsion??

 

Hi to all...no, RP=restricted performance
Keep us up to date, what the OBD-scan resulted in..

Cheers, Alex

 

Got it, thanks.

 

Yeah, but I meant to say that the switch can cause failsafe, which is what you have!

 

12.2VDC quiescent is too low.

What happens is that the starter draws down your voltage
during startup, your ecu goes crazy because it has insufficient
voltage to operate.

As an interim test, every time you use your car, turn the key to
position 1, wait for self-check to complete as indicated by most
dash lights going out, then start. If this reduces your problems,
it points at the battery.

Or, completely charge your battery using a battery charger. It
should show 12.8VDC when quiet.

A complete charge can take 24-48 hours.

 

Thanks for the advice plums. I'll check it out. I recognize my battery voltage test wasn't a load test. I'll have that checked at my local parts store.