B2798 · blink 99 – COMMUNICATION MALFUNCTION NO.2

System: Engine immobiliser
Dashboard light: Security indicator light (symptom); check RM 05-818 for read method
Applies to: Cars with engine immobiliser
Check-engine blink code: 99
Description: COMMUNICATION MALFUNCTION NO.2
Detection / symptoms: Detection: Communication error
Possible causes: Key; Transponder key amplifier; Wire harness; ECM
What to check: Workshop check order (RM821E): CHECK HARNESS AND CONNECTOR BETWEEN TRANSPONDER KEY -> CHECK TRANSPONDER KEY AMPLIFIER
Confidence: high (official Toyota RM821E)

From the factory service material. Clear the code and test-drive to confirm it returns. Search all fault codes · Common problems · Warning lights