Operation CHARM
: Car repair manuals for everyone.
Home
>>
GMC Truck
>>
1999
>>
S15/T15 Sonoma P/U 2WD L4-2.2L VIN 4
>>
Repair and Diagnosis
>>
Relays and Modules
>>
Relays and Modules - Powertrain Management
>>
Relays and Modules - Computers and Control Systems
>>
Engine Control Module
>>
Description and Operation
>>
HO2S Heater
HO2S Heater
The oxygen sensor heaters are required by catalyst monitor sensors to maintain a sufficiently high temperature which allows accurate exhaust oxygen content readings further from the engine.