I have a 2007 XJ8L with 63K miles. I live in California where the smog check is incredible strict and last year it took months due to one of the Emission Monitors not being 'ready'.

This year all 9 EM are good, but I have an Engine Code "U0426 - Invalid Data Received From Vehicle Immobilizer Control Module"

The car has no check engine light on, nor any other abnormal function lights or messages. Everything works fine and drives great.

The issue is what this 'U0426' message means and the impact it will have when trying to get the smog certificate.

Any insights are very much appreciated -

Thanks,
Stephen Taylor

 

Leave it alone. If the MIL is off it's not current.

Don't clear it!! If you do you'll clear (unset) all those monitors you need set.

 

Thanks JagV8 -

Not sure what "If the MIL is off it's not current" means?

Can you please educate me on this?

Thanks very much -

 

MIL - see below.

 

MIL is short for Malfunction Indicator Light. If you don't have a light on your dash (check engine), then leave it be. JagV8 is saying that you're just seeing an old code in your history.

 

But why did he say dont clear the code and need the set values??

what does that mean, i clear codes all the time is that wrong? i mean ill stop doing it if it is but will be scratching my head wondering why

 

Not sure, but it may be because of the problem we had passing the California smog test last year due one not ready sensor, the 'Secondary Air System'.

We had a dead battery which cleared all the sensors. We then drove the car over 1,000 miles in all sorts of traffic and travel and that sensor never showed ready.

As a result, we went to the Jaguar Dealer who charged us $350 and had the car 4 days, and was not able to get the sensor to show 'Ready'.

We then had to make a special appointment with he California Bureau of Automotive Repair (BAR), drive almost an hour to get there, and they messed with it for another two plus hours.

The good news is that although the sensor never showed ready, they did have the authority to 'pass' the vehicle, which is good for two years.

That was last year and I regularly check the OBD to see what's happening. Finally, this week, the Secondary Air System sensor went green, so now all sensors are ready.

With this problematic past, the last thing we want to do is clear the code which will also clear the 'ready' sensors. That may start us down another rabbit hole trying to get all 9 sensors 'ready' again.

I called the smog test station today and they said that as long a there is no MIL and all sensors are 'ready', then there will not be a problem passing the test with that U0426 code showing.

Thank you California -

 

Completely wrong. Fix the fault instead. (The code will auto-clear anyway if you do.)

Every clear also clears the OBD monitors.