C70, S70 & V70 (Temperature Gauge Does Not Work)

Check if DTC 123 is present. See ENGINE PERFORMANCE article. If DTC 123 is present, there is no temperature signal going to Motronic ECU or it is shorted to ground, voltage or both. If DTC 123 is not present, check for an open circuit in temperature signal Green/Gray wire between instrument cluster 30-pin connector terminal A26 and Motronic ECU connector terminal B23.