Dirt cheap XJ OBD-II engine monitoring with your smart phone

travisk · Nov 21, 2013

Monitoring your 96+ XJ's OBD2 system has become ridiculously cheap and simple over the last few years. All you need is an iPhone, Android or tablet along with a cheap ODB2 device. What used to cost thousands of dollars can now be done for $30 or less.

I picked up an ELM327 reader from Amazon for about $20. There is a WiFi version for Apple devices or a Bluetooth version for Android (Bluetooth is easier to use but Apple doesn't support it unless you jailbreak your phone.)

Then download one of the numerous compatible ODB2 apps to your phone. I'm using DashCommand, which seems to be the best option for iPhone users. It cost me $10. There are plenty of good options for Android, too.

Once you hook it up, the OBD2 reader will stream all kinds of information to your phone. RPM, power, torque, timing, coolant temp, intake temp, fuel economy, etc.

Of course you can view and reset diagnostic codes, too.

Anyone have any other apps to recommend?

TheCaptain · Nov 21, 2013

Torque Pro is the best app for android

Olympus Off Road · Nov 21, 2013

I have the same adapter and the Torque Pro app. Works great.

I keep it plugged in on my truck with an LS conversion until I get some real Gauges in there.

JeepNovice · Nov 22, 2013

That's awesome. Just ordered one, it ll be nice to have.

DrMoab · Apr 17, 2014

Curious. With Dash command is it always in portrait mode or will it switch to landscape mode too?

sidewaysstarion · Apr 17, 2014

It'll work in landscape mode, but if I remember correctly you had to set what mode you were going to run it in in the skin settings.

DrMoab · Apr 17, 2014

Thanks brainy dude.

travisk · Apr 17, 2014

It turns out that DashCommand can read OBD2 trouble codes from my XJ but it fails to reset them.

lazyxj · Apr 17, 2014

Interestingly, the ELM327 works fine in the 1997 XJ, but sets a CEL (P1694) in the 2001, which will not start until the ELM is unplugged and the code cleared.
Wonder if another brand of OBDII Wifi device would work or if this problem is unique to the 2001 XJ? (dual mini-cats).

iluv83vettes · Apr 17, 2014

travisk said:
It turns out that DashCommand can read OBD2 trouble codes from my XJ but it fails to reset them.

I have also found this to be the case.

Hopkins · Apr 18, 2014

Do any of these apps allow for tuning? Or even recalibration for larger tires?

iluv83vettes · Apr 18, 2014

The speedometer is driven by a gear and cable so you can't adjust for larger tires with electronics.

lazyxj · Apr 18, 2014

iluv83vettes said:
The speedometer is driven by a gear and cable so you can't adjust for larger tires with electronics.

All OBDII XJs use an electronic speedometer and sender.
Speedometer cables went out years ago.

A good program or OBDII monitor can be adjusted to show the correct MPH. I have been using a ScanGauge for ten years and it allows speed adjustment.
None of these programs allow any tuning, they just show the information available on the OBDII port.

DrMoab · Apr 18, 2014

lazyxj said:
Interestingly, the ELM327 works fine in the 1997 XJ, but sets a CEL (P1694) in the 2001, which will not start until the ELM is unplugged and the code cleared.
Wonder if another brand of OBDII Wifi device would work or if this problem is unique to the 2001 XJ? (dual mini-cats).

The jeep won't start until the code is cleared?

DrMoab · Apr 18, 2014

Lemur makes a free app similar to dash command but not as detailed. My wifi plug should be here tomorrow. I'll see if I can clear codes with it if dash command won't.

87manche · Apr 18, 2014

travisk said:
It turns out that DashCommand can read OBD2 trouble codes from my XJ but it fails to reset them.

this is a problem with the cheap adapter.

lazyxj said:
Interestingly, the ELM327 works fine in the 1997 XJ, but sets a CEL (P1694) in the 2001, which will not start until the ELM is unplugged and the code cleared.
Wonder if another brand of OBDII Wifi device would work or if this problem is unique to the 2001 XJ? (dual mini-cats).

also a problem with cheap adapter.

I have had no issues out of my Kiwi PLX and a CA emissions 01 XJ using dashcommand or torque.

It's been connected for weeks at a time while we were traveling doing datalogging and the like. I have used it to clear codes.

http://www.plxdevices.com/product_info.php?id=GSST2WIFI

I have a bluetooth one because I use Android. Redheep has a wifi one he uses with iphone with no issues.
spend the money on a decent adapter and you'll be happy.

lazyxj · Apr 18, 2014

DrMoab said:
The jeep won't start until the code is cleared?

Yes, the 2001 just cranks, clear the code and it starts. My 01 loves setting CEL codes so much that I carry a scanner under the seat.
The 1997 XJ isn't effected at all by the ELM327.
The 2001 has a more complex OBDII system, with the dual mini-cats, 4 O2 sensors, the distributor-less ignition and who knows what else.
Something about it does not agree with the ELM327. I'm going to try another brand of OBDII WiFI device.

DrMoab · Apr 18, 2014

How do you go about clearing the code? Since the reader won't let you.

lazyxj · Apr 18, 2014

DrMoab said:
How do you go about clearing the code? Since the reader won't let you.

Using a handheld OBDII code reader.
The ScanGauge does not always clear CEL codes either.

87manche · Apr 18, 2014

I'm fairly certain it's a result of the baud rate of the 01 bus.

I'd have to look and see what dashcommand auto negotiates at in the 01.
again, the PLX adapter has been flawless for me. I've plugged it into 2010 vehicles and stuff as old as a 1996 Pontiac sunfire.
Never had an issue.

Dirt cheap XJ OBD-II engine monitoring with your smart phone

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