oddites of smog parts. EGRT is first. (EGR sensors) USA only last year was 1995, EGR ended for OBD2 next year 96. The EGR EGRT thermistor thermoprobe.EGRT EPC Epartscat data.Suzuki (GM unknown, EGR usage exact dates) The secret rule of this EGRT sensor... All 8v calif 89 to 91 (no fed car has it these years) the ecu is not unique cal/fed the ecu has an extra ground pin on the calif harness to tell ECU (this is California use the EGRT) This is pin A4 and if you want to stop using the EGRT , just cut this ground wire at ECU pin A4. simple huh? The map sensor is now used to measure EGR performance. 92-95 EGRT 8v. all 92-94 cal only but 95 all 8v have EGRT , same ground A4 rules 92-95': 16 ECU are unique for EGR. and autotest it at boot, and throws 53 if not found. 16V engines EGRT fitted to all 2 door cars. 16v EGRT begans on all 4door cars Calif, 92/93 and all 94/95 Fed/cal cars of this type. 16v,all 94/95 federal and calif. In all sidekick/Trackers, if your year does not use the Thermoprobe , then that means it uses the MAP sensor (8v) or a dedicated MAP in the 16v and EGR-MAP 1996 to 1998 and beyond. If you mix EGR parts, car bodies or ECU , you may get code 53, wrong EGR DTC. The harness has an extra ground pin to the ECU, in all calif. 8v kicks. In years, with EGRT sensors. the ECU senses that the probe is missing, and throws 53s. A hack: a 10,000 ohm resistor in place of the EGRT proble, fools all ECU into thinking all is well. Ending 51 forever. The resistor shows hot all the time and the DAFT ECU believes this? wow. The IAT sensor was not present on 16v cars the first year, 1992 was devoid of it , then added it in 1993 year. the IAT is found. at the air cleaner box, just behind the MAF. the new intake manifold with the 4mm thermostat rubber gasket started in 1995 vin R64xxxx~ The ECU varies for all engines and years including ,Fed/cal, EGR revisions, added IAT in 93 door count (weight) tranny, 2wd/4wd, In 1996 OBD2 changes all designs and parts. no more EGR but keeps the funky vacuum EGR parts, including the EGR modulator and the need of a cat to sense loads for proper EGR FLOW. IN 1999 the EGR changed radically to a motor EGR , just one simple part. no more modualor or the need for a CAT .