P1690 BMW Fault Code

Description:

The input turbine speed sensor detects rotation of the input shaft of the input shaft speed sensor transmission. The computer uses that information, along with the output shaft speed sensor to determine if the transmission is operating according to plan. If the computer detects a difference between the input shaft speed , and the expected output shaft speed, it will adjust transmission pump pressure to prevent clutch disc slip. If adding pressure doesn't solve the problem, it will set a trouble code.

P1690 Code Symptoms :

There are currently two main types of cylinder deactivation used today, depending on the type of engine. P1690 code for the pushrod design which uses solenoids to alter the oil pressure delivered to the lifters. In their collapsed state, the lifters are unable to elevate their companion pushrods under the valve rocker arms, resulting in valves that cannot be actuated and remain closed.

Diagnosis And Repairing P1690

P1690 OBD 2 code on vehicles with electronically controlled automatic transmissions, the 3-4 shift solenoid is responsible for actuating the hydraulic circuits to activate clutches or bands that change gears inside the automatic transmission.

How to fix P1690 code ?

• Damaged VCT phaser
• Faulty Camshaft Position Sensor
• Insufficient cylinders compression
• Open VPWR circuit

Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code P1690, so consult the manual to locate the brake fluid reservoir.

Bear in mind that a low fluid level can set code P1690 on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.