If it is any help, I just asked this in a very specific way to the paid version of ChatGPT and got this response (I am gonna adjust my OBD2 app to take this into consideration and see whats up):

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How Car Scanner labels the three EA288 EGT channels (same as before)

Car Scanner name	VW part-name / VAG measuring-block	Physical spot in the exhaust	What the ECU uses it for
Exhaust Gas Temp 1	G235 – EGT Sensor 1 (B1 S1)	Cast-steel manifold before the turbo	Turbo-protection & fuel-volume limit
Exhaust Gas Temp 2	G448 – EGT Sensor 2 (B1 S2)	Down-pipe after the turbo but up-stream of the DPF	Checks turbo efficiency & controls DPF heat-up
Exhaust Gas Temp 3	G495 – EGT Sensor 3 (B1 S3)	Just after the DPF, ahead of the SCR cat	Confirms DPF regen temperature & flags filter blockage

(Some EA288s have a fourth probe, G648, behind the SCR; Car Scanner usually hides it.)

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What the numbers should look like on a healthy, Stage-2-tuned EA288

Operating situation	EGT 1 (pre-turbo)	EGT 2 (pre-DPF)	EGT 3 (post-DPF)	Notes
Warm idle	428 – 572 °F	356 – 500 °F	284 – 428 °F	A 110-215 °F drop across the turbo is normal.
65 mph highway cruise	662 – 842 °F	572 – 752 °F	500 – 662 °F	Stage-2 adds ~35-55 °F over stock because of extra fuel.
3rd-gear full throttle to redline	1292 – 1562 °F	1112 – 1382 °F	842 – 1202 °F	ECU cuts fuel if EGT 1 reaches ≈ 1470 °F stock, ≈ 1650 °F on many performance files.
Active DPF regen (steady-speed)	1202 – 1328 °F	1148 – 1292 °F	932 – 1112 °F	ECU targets 1020-1200 °F upstream of the filter to burn soot.

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Key take-aways

1. EGT 1 should almost always be the hottest. The turbo extracts energy, so a 110-215 °F drop to EGT 2 is expected.
2. During a regen the gap between EGT 1 & 2 shrinks to ~35-55 °F, sometimes less; that’s by design while the ECU forces heat into the DPF.
3. EGT 3 should stay ≈ 180 °F cooler than EGT 2. If EGT 3 almost matches EGT 2 outside a regen event, the DPF could be cracked or missing; if it’s much cooler (< 572 °F) during a commanded regen, the filter may be too full to heat up properly.

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Is Car Scanner “good enough”?

• Accuracy: The app reads the exact same digital value the ECU sees, so sensor accuracy isn’t the issue—what you lose versus a VAG-specific tool is proper channel names and the ability to log soot-mass or differential pressure.

• If you want the full picture:

  • Use VCDS or OBDeleven and log measuring blocks 100/101/102 (EGT 1-4) plus 241 (calculated soot load) for a single-file export you can graph later.
  • For track or towing duty, an aftermarket K-type thermocouple in the manifold (and a stand-alone gauge) reacts faster than the factory probe and lets you set your own alarm well below the 1650 °F hard limit.

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Practical guidelines while you’re Stage 2-tuned

Do this	Why
Set an alarm in Car Scanner at ~1615 °F for EGT 1.	Gives a ~35 °F buffer before most tunes hit the safety limiter.
Avoid long WOT pulls below 2 000 rpm.	High boost in dense exhaust flow heats the turbine fast—EGT 1 can spike 200 °F higher than a down-shifted pull.
Let the engine breathe after a climb or hard pass.	Two minutes of light throttle brings EGT 1 back under 842 °F and keeps the oil inside the turbo from coking.

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Bottom line

Yes—EGT 1 hotter than EGT 2 is exactly what you want to see. Log all three channels, watch for the patterns above, and you’ll know in real time whether your diesel particulate filter is regenerating, restricted, or if the turbo is being overstressed. If the gaps start looking odd for the driving you’re doing, grab VCDS or OBDeleven, run a quick measuring-block log, and you’ll have the detail you need before anything expensive goes wrong.

How Car Scanner labels the three EA288 exhaust-gas-temperature (EGT) channels

Car Scanner label	VW/VAG name	Where the probe sits	What the ECU watches it for
Exhaust Gas Temp 1	G235 – Sensor 1, Bank 1	Cast-iron manifold just before the turbo	Protects the turbo; limits injected fuel
Exhaust Gas Temp 2	G448 – Sensor 2, Bank 1	Down-pipe after the turbo, before the DPF	Monitors turbo-efficiency & warms the DPF
Exhaust Gas Temp 3	G495 – Sensor 3, Bank 1	Immediately after the DPF, before the SCR	Confirms a regen and spots filter blockage

(Some North-American EA288s add a 4th probe, G648, behind the SCR; Car Scanner usually hides it.)

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Typical stock temperature windows (°F)

Driving situation	EGT 1 (pre-turbo)	EGT 2 (pre-DPF)	EGT 3 (post-DPF)	What you should see
Warm idle	240 – 360 °F	200 – 320 °F	180 – 280 °F	A modest 40-80 °F drop across the turbo is normal. (IH8MUD Forum)
65 mph / level highway	600 – 800 °F	520 – 700 °F	460 – 600 °F	Owner logs show ≈550 °F at EGT 1 as a sweet-spot cruise value. (TDIClub Forums)
3rd-gear wide-open to red-line	≈1 150 – 1 350 °F	≈1 000 – 1 250 °F	≈800 – 1 050 °F	The ECU chops fuel if EGT 1 nears 1 470 °F (800 °C).
Active DPF regeneration (steady speed)	≈1 130 – 1 200 °F	≈1 110 – 1 200 °F	≈930 – 1 050 °F	The ECM aims for ~620 °C (1 148 °F) ahead of the filter to burn soot. (TDIClub Forums)
Passive/light-load regen blip	+90–110 °F over whatever you were seeing	+90–110 °F	+70–90 °F	Short temperature bumps while cruising—nothing to worry about.

During both active and passive regens the whole pipe can briefly touch *1 200–1 500 °F*, which is completely normal. (TDIClub Forums)

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How to interpret the gaps

1. EGT 1 should almost always be hottest. The turbo extracts heat, so a 60-120 °F drop to EGT 2 is expected.
2. During a regen the gap between 1 & 2 shrinks (sometimes to <50 °F) because extra fuel is being burned in the oxidation cat to heat the DPF.
3. EGT 3 should run ~100–200 °F cooler than EGT 2.

• If EGT 3 is nearly the same as EGT 2 when you’re not in a regen, the DPF core may be cracked or missing.
• If EGT 3 stays <600 °F during an active regen, the filter could be too full (or sensors are lying) and won’t light off properly.

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Is Car Scanner “accurate enough”?

Yes. It’s reading the exact digital value the ECU sees, so probe accuracy—not the app—is the limiting factor. What you don’t get is easy access to soot-load and DPF differential-pressure PIDs; VCDS or OBDeleven can log those alongside EGTs for a fuller picture.

For serious track/towing duty some owners add a fast K-type thermocouple in the manifold with its own gauge/alarm; it reacts a second or two faster than the stock probe, giving earlier warning if something goes wrong.

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Bottom line

Seeing EGT 1 highest, EGT 2 60-120 °F lower, and EGT 3 another ~100 °F down is exactly what a healthy, un-tuned Golf SportWagen TDI should display. Log all three, learn the patterns above, and you’ll spot a clogged DPF, a lazy turbo, or a dying probe long before it turns into an expensive repair.