Infiniti QX80 Transmission Temperature and JR711E Live Data with ELM327

The 2011–2013 Infiniti QX56 and the 2014–2024 QX80 (Z62) use the Jatco JR711E, also known as the RE7R01B. It’s the heavy-duty version of the 7-speed, rated for up to 442 lb-ft (600 Nm) behind big V8s. It holds up well but is expensive to rebuild, and trouble starts quietly: slightly hotter fluid, a small rpm flare on a shift, a converter that no longer locks up fully. You won’t feel it yet, but you’ll see it in the data.

The “Transmission” screen in Canfiti streams live data from the transmission control unit (TCM), essentially what a dealer sees in the CONSULT Data Monitor. Below are the readings worth checking first and a 15-minute routine to tell whether the transmission is healthy.

Which vehicles this covers

The screen is verified on the QX56 Z62. A QX80 owner uses it to watch fluid temperature during fluid changes. On other vehicles with this transmission it may work too: connect and see.

Opening the “Transmission” screen

You need Canfiti 0.6.0 or newer. Plug the adapter into the OBD2 port under the dash on the driver’s side, start the engine, and connect. On the main screen, tap “Transmission”. Within a couple of seconds the TCM number appears on the “ECU part number” card at the bottom. “Not connected” there means the adapter or the TCM didn’t respond.

Data keeps refreshing while the screen is open. It’s split into ten groups, from “Gears and selector” to “Indicators and status”. Flags show as 0 (off) or 1 (on), and temperature and speed follow your unit settings.

The six readings to check first

1. Fluid temperature

You get two values: “ATF Temperature of oil pan” and “ATF Temperature of torque converter outlet”. There’s only one physical sensor. The first number is calculated from its signal; the second is the TCM’s estimate for the converter.

For most automatics, about 170–225 °F (77–107 °C) is a normal operating range, according to CarParts.com. Towing, sand, or summer traffic can push it higher briefly. Overheated fluid breaks down, varnishes the valve body, and harsh shifts follow.

Sensor sanity check: on a cold morning the reading should be close to the outside air. Exactly −67 °F or 392 °F (−55 or 200 °C) means the end of the scale, which points to an open or shorted sensor or wiring. Cross-check with “ATF temperature sensor 1 (voltage)”: it’s a thermistor, so hotter fluid means lower voltage.

2. Gear ratio vs. target

“Gear ratio” is what’s happening; “Target gear ratio (7AT34)” is what the TCM wants. In a gear with no shift in progress, they match and hold steady. If the actual ratio wanders, a clutch is slipping. Factory ratios from the official 2022 Infiniti QX80 specifications:

A difference of 0.001 is just rounding.

3. Torque converter slip

Engine rpm minus input shaft rpm. Pulling away and accelerating, a few hundred rpm is normal. Then lock-up kicks in: in 2nd through 5th it runs with a small, controlled slip, and in 6th and 7th it can lock the converter solid, per the ATSG manual. With cold fluid, there’s no lock-up. The easiest place to check is a steady cruise in 6th or 7th, where slip should be almost zero.

According to gearboxlist.com, the lock-up clutch is the JR711E’s weak spot: it wears, and debris in the fluid clogs the valve body passages. After temperature, this is the number to watch.

4. Solenoids: command vs. monitor

Each solenoid has a pair of values in amps: the current the TCM commands (“Line pressure solenoid”) and the current it measures in the circuit (“L/P solenoid monitor”). On a healthy transmission they’re nearly equal. A clear, persistent gap means checking the wiring, the valve body connector, or the solenoid itself. Two labels are internal names: “Solenoid 7AT25” is the 2346/B solenoid, and “P062F exclusive function” is the D/C solenoid monitor.

5. Fail-safe and overheating

“Fail-safe indicator lamp” and “ATF warning lamp” should always read 0. A 1 on the first means limp mode: limited gears and harsh shifts. A 1 on the second means the fluid is overheating.

6. Lever position

“Shift indicator” and “Select lever position” follow the lever, and “Range switch 1–4” give their own 0/1 pattern for P, R, N and D. If the TCM sees N while you’re in D, the range sensor is the likely culprit.

15-minute health check

Do it every couple of months, or on a used truck before you buy.

Parked, engine running:

1. Both fault flags read 0.
2. Fluid temperature looks believable, with no −55 or 200 °C.
3. Press the brake and “Brake switch” goes to 1; release it and it goes to 0.
4. Foot on the brake, move the lever slowly P → R → N → D and into the manual gate. “Shift indicator” shows the same letter, “Range switch 1–4” don’t flicker once the lever stops, “Start relay monitor” reads 1 only in P and N, and “Manual mode indicator” comes on in manual.
5. In each solenoid pair, command and monitor are nearly equal, and “ON/OFF solenoid” matches its monitor.
6. In N, “Input speed” is close to “Engine speed”.
7. In P or N, touch the gas: “Throttle position” rises from 0 and “Idle switch 7AT74” flips from 1 to 0.

On the road, fluid warm:

1. Gentle acceleration to 60 mph: gears come in order, and “Next gear” runs a moment ahead of the current one.
2. Each gear holds a steady ratio that matches the target and the factory number.
3. Rpm moves smoothly through each shift, with no brief flare.
4. Cruising at 50–60 mph in 6th or 7th, “Target pressure TCC” is high and slip stays within a few dozen rpm.
5. Kickdown: throttle reaches 8, “Without throttle position” goes to 1, and the transmission drops gears quickly.
6. “Vehicle speed sensor A/T” roughly matches the speedometer.
7. After 20–30 minutes, temperature levels off around 170–225 °F.

If everything checks out, the transmission is most likely fine. Keep up with fluid changes and keep the cooler clean.

Red flags

One odd number isn’t a verdict. Check whether it repeats and whether it matches what you feel from the seat.

Engine won’t crank? Check the TCM

On these trucks the starter only works in P and N, and the TCM grants permission through its starter relay output. “Start relay monitor” shows what the TCM is putting out right now.

Turn the ignition on without trying to start. Open “Transmission”, put the lever in P, then, foot on the brake, in N, R and D. Watch “Start relay monitor”, “Shift indicator” and “Range switch 1–4”.

• 1 in P and N, 0 in R and D. The transmission is giving permission. Keep looking: battery and terminals, the underhood relay, the starter, the key system.
• 0 in P and N, and the selector reads wrong, or the range switches don’t change. The TCM doesn’t see P or N. Suspect the range sensor, its adjustment, or its connector. The classic symptom is a truck that only starts in N or after you wiggle the lever.
• 0 in P and N with the selector reading correctly. The problem is in the starter relay circuit or the TCM itself. Time for an auto electrician, and bring these numbers.
• 1 in R or D. That shouldn’t happen. Check the range sensor.

If other units respond but the TCM doesn’t, it has a power or communication problem. Read the monitor before cranking, since voltage dips and the adapter may drop out. A 1 only means the TCM gave permission, not that current reached the starter.

Keep in mind

Factory tolerances for this transmission aren’t publicly available, so the temperature and slip numbers here are guidelines, not specs. This screen doesn’t replace a proper diagnosis, but walking into a repair shop with numbers beats “it jerks sometimes”. More on the transmission page and the QX80 and QX56 Z62 page.