Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P1891: Problem in Start Clutch Control System: General Description
The start clutch control system controls the clutch piston hydraulic pressure that affects the amount of power transmitted by the multiplate wet start clutch on the driven pulley shaft. The powertrain control module (PCM) activates the CVT start clutch pressure control solenoid valve to control the hydraulic pressure that is applied to the start clutch piston in accordance with vehicle conditions. The start clutch control system detects clutch overslip. If the difference between the vehicle speed measured by the CVT output shaft (driven pulley) speed sensor and the one measured by the vehicle speed sensor is excessive when driving the vehicle under the Enable Conditions, the PCM detects a malfunction and stores a DTC.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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