P1290

What the Code Means

P1290 is described in the source as a high input signal level in the cylinder head temperature (CHT) sensor circuit. The CHT sensor sends cylinder head temperature data to the control module, and an elevated signal disrupts the logic that governs engine temperature management.

The code also notes that the electric wastegate valve fails to reach the required position during the catalytic converter warm-up phase. That disrupts the exhaust gas delivery needed to heat the converter after a cold start. Wastegate adaptation during the cold-start phase doesn't run.

Symptoms

• The electric wastegate doesn't reach the required position during the catalytic converter warm-up phase after a cold start.
• Exhaust gas flow control needed to heat the converter is disrupted.

The source has no data on other symptoms (warning lights, engine behavior).

Diagnosis and Repair

1. Check the wastegate linkage for damage and signs of wear.
2. If the problem persists, replace the electrical controller drive or the wastegate valve.

The source doesn't cover CHT sensor circuit test methods, reference values, or common diagnostic mistakes.

Secondary Problems

• The source notes a risk of head gasket failure if the engine overheats.
• A possible water pump or thermostat fault is also discussed.

Severity is rated moderate, but don't put off diagnosis given the overheating risk.