Guide · Link ECU

EGT on Link ECU

A Link G4X reads an exhaust gas temperature amplifier on an An Volt input, as a GP Temperature channel with a two-point linear calibration. This guide covers the inputs, the wiring, the PCLink setup, and the error limits that matter for a sensor that reads close to 0 V when cold.

Checked against Link's quick-start guides and manuals and answers from Link staff on the Link forum, September 2026. Menu names are from PCLink for G4X and G5 ECUs. G4+ ECUs use older software with different menus, so these steps won't match.

00What you need

• A Link G4X ECU with a free An Volt input, and PCLink connected to it.
• An EGX5 for the ECU's +5V supply, or an EGX12 for a key-on 12 V feed. Either one needs an ungrounded Type K probe; the kits include one.
• A multimeter.

01Pick an input

Use an An Volt input. An Volt inputs have no internal pull-up. An Temp inputs have one for thermistors, so leave those for temperature sensors. On a plug-in, use a spare An Volt on the expansion connector.

• How many: AtomX has An Volt 1–3, MonsoonX 1–4, StormX 1–8, FuryX 1–9 and XtremeX 1–11.
• Plug-in ECUs: spare An Volts are on the expansion connector, for example An Volt 5 and 6 on a WRX V3–4 plug-in. Check your model's pinout.
• Range: 0–5 V.

02Wire it

• Sensor ground, even on 12 V. Link staff advise connecting an amplifier's ground to sensor ground even when it runs on 12 V. Sensor ground never goes to the block or chassis.
• EGX12 supply: use a fused key-on 12 V feed that stays on while cranking. Don't use +8V Out: only some ECUs have it, and 8 V is the bottom of the EGX12's supply range.
• Don't overload +5V. Your other sensors share it. The EGX5 adds under 2 mA.
• Use the sensor ground, not chassis. Every 4–5 mV of ground offset reads as about 1 °C.
• An EGX5 goes on a 5 V sensor supply only, never 12 V. It has no reverse-polarity protection either, so check red and black before you power up.
• Both outputs stay near 5 V, even in a fault. The EGX5 can't rise above its own 5 V supply, and the EGX12 is capped at about 5.3 V.

Probe side

• Kit: the probe plugs into the mini-K socket.
• Module only: yellow to the probe's +, red to −, spliced right at the module.
• Need more reach? Extend from the probe end with Type K extension wire, never copper.
• Ungrounded probes only. An ohmmeter from either lead to the sheath should read open.
• Mount the module somewhere cool, on the cabin side of the firewall or an inner fender: under 50 °C for an EGX5, under 100 °C for an EGX12.

03Set it up in PCLink

1. Set up a calibration: find Linear Cal 1 in PCLink's settings tree (type “linear” in its search box). Set Label to EGT and pick Output Units. Enter Input Value A 0.000 V with Output Value A 0. Then enter Input Value B and Output Value B from the table below.
2. Open Analog Inputs → GP Input → GP Temperature 1 and set Source to the An Volt you wired. Set its calibration to Linear Cal 1.
3. On the An Volt, set Error Low to 0.00 V and Error High to 5.00 V, so no real reading counts as a fault. While an input is in fault, PCLink uses the Error Value instead of the reading, and so does any warning light or limit that uses it. An open probe already reads hot.
4. Store it with F4, Ctrl+S or ECU Controls → Store to ECU. Changes take effect straight away, but are lost at power-off until stored.

Calibrate to the amplifier's 0–5 V range, not to the probe's rating. Press U in PCLink to change units, including °C or °F.

A dash means past that model's range.

04See it and log it

• Runtime Values (F12 or R) shows GP Temp, and the An Volt's voltage and status (Active, Off or Fault).
• Put a digital gauge for it on a PCLink page.
• PC logging: add it under Logging → Setup Logging, on the PC Logging tab, then press F8 to start and stop. ECU logging: same window, ECU Logging tab.
• To show it on a CAN dash, add the GP Temperature to a CAN user stream.

05Optional: a warning light or protection

A GP Temperature can drive an output or feed a limiter.

1. Warning light: a General Purpose Output, with SW Parameter 1 set to your GP Temperature, SW Cond 1 set to >, and your limit in the row below. On Delay and Off Delay are there too.
2. Protection: GP RPM Limit 1 or 2 can put the EGT on a table axis, with Startup Lockout and Activation Delay.

06If something's wrong

PCLink logs “An Volt below Error Low Value”

Error Low is above 0 V. The EGX reads close to 0 V when cold, so set Error Low to 0.00 V, then clear the codes under ECU Controls. If one comes back, Store, power-cycle and clear it again.

GP Temperature shows a fixed value

The input is in fault, so PCLink shows the Error Value instead of the reading. Check the An Volt's status in Runtime Values.

Every sensor reads slightly wrong

Check the 5 V supply: it should measure very close to 5 V at the +5V pin. Fault code 74 is a 5 V supply error, usually from a mis-wired sensor.

It reads near full scale on a cold engine

The probe is unplugged or open. Both modules drive their output high when the probe circuit is open, so an open probe reads hot, not cold.

The reading jumps with revs, fans or the alternator

You have a grounded probe, or the black wire is on chassis ground. Fit an ungrounded probe and use the sensor ground.

It reads high once the engine bay heats up

The module is mounted somewhere too hot, or there's copper wire between the probe and the module.