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Home >> Lexus >> 2025 >> NX 350h >> Repair and Diagnosis >> External Pages >> Different car >> Section 64 (Stop And Start System - Diagnostic Codes (1 Of 2)) >> Stop And Start System >> DTC P1644-00: ECU Malfunction (Starter Circuit) [03/2023 - ] >> Typical Malfunction Thresholds

Typical Malfunction Thresholds

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CASE 1, CASE2, CASE5

Engine stop and start ECU starter relay voltage Higher than [Battery voltage x 0.44] V
CASE 3

Either of the following conditions (a) or (b) is met -
(a) Engine stop and start ECU starter relay voltage [Battery voltage x 0.44] V or less
(b) Engine stop and start ECU starter relay voltage [Battery voltage x 0.88] V or higher
CASE 4

Engine stop and start ECU starter relay voltage Less than [Battery voltage x 0.88] V
CASE 6

Engine stop and start ECU starter relay terminal voltage level Low
CASE 6

Starter relay overcurrent Detected
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