Powertrain
generic / SAE
P0599
Thermostat Heater Control Circuit High
Same as P0597 with the control line shorted to supply. The sensor heater warms the element to operating temperature (~600 °C); without it the lambda sensor stays inactive in closed loop and the ECM cannot trim mixture.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number5 / 99
Possible causes
- Control line shorted to supply high
- Connector pins corroded - high contact resistance low
- Supply wire pinched against B+ source low
Inspection / repair
- Difficulty: medium
- DIY: possible
- Estimated cost: 80–350 €
- Estimated time: 0.5–2 h
- Component: map thermostat heater
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012