OBD-II Live Data Display - Scangauge / Ultragauge (1996-2001)
Scangauge II ($170) or Ultragauge ($80) plugs into the OBD-II port and displays live PCM data — coolant temp, trans temp (via PCM PID), AFR, voltage, MPG, even trip computer. Great alt to physical gauges on 1996+ XJ.
1996-2001 XJ has OBD-II. The PCM monitors trans temp (via the trans solenoid pack), coolant temp, air intake temp, MAP, MAF (none on stock), short/long term fuel trim, O2 voltages, and timing. All of this is readable via a $20 OBD-II Bluetooth adapter + Torque Pro on Android, or a dedicated unit:
- Scangauge II ($170): the standard. Dedicated screen, runs 4 gauges + trip data, X-Gauge custom PIDs let you read trans temp from the PCM directly (PID 195C or similar — varies by year). Reliable and stays in the truck.
- Ultragauge EM Plus ($80): similar functionality, larger screen, slightly cheaper. Less polished UI.
- Bluetooth OBD2 dongle + Torque Pro on Android phone ($30-50 total): cheapest path, screen-on-demand, can log to SD card.
What to display: trans temp, coolant temp, instant MPG, battery voltage, and clear-codes shortcut. For SOA/heavy use, trans temp from PCM is comparable to a real trans temp gauge if you trust the sender (it's near the solenoid pack, reads pan-ish temp).
Pre-1996 (OBD-I): no OBD-II port, requires AMC/Chrysler-specific scan tool. Scangauge will NOT work. Stick with physical gauges.
Why it works
- multiple parameters, one device
- trans temp without drilling
- OBD-II code reader built in
Trade-offs
- 1996+ only
- X-Gauge setup requires correct PID per year
Tools required
- nothing - plugs into OBD port
Parts
| Part | Vendor | Est. price |
|---|---|---|
| Scangauge II | Linear Logic | ~$170 |
| Ultragauge EM Plus | Ultragauge | ~$80 |
| OBDLink MX+ Bluetooth dongle | OBD Solutions | ~$90 |
Sources
Related
- Transmission Temperature Gauge (AW4 / AX15)
- Aux Gauge Cluster - Voltmeter / Oil Pressure / Trans Temp
- All Jeep Cherokee XJ guides & tools
- Browse the full DIY database
Written and maintained by an AZ wheeler and driveway wrencher. How we source guides. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.