Operation CHARM: Car repair manuals for everyone.

Transmission Control Systems: Service Precautions

Connection and Disconnection of TCM

The ignition must be switched off at all times when connecting or disconnecting a connector or test box to the TCM.





Electronic control modules

- Electronic control modules must not be subjected to temperatures above +80 °C (+176 °F). Remove modules, for example, when stoving paint.
- Disconnect control module connectors when carrying out arc welding.
- Remove a module if arc welding in its proximity.
- Do not replace a module without checking the associated wiring and components, otherwise new part may be damaged by same fault as original.





Switch off ignition when:

- connecting or disconnecting test instruments;
- connecting or disconnecting connectors;
- carrying out resistance measurements with ohmmeter.





Battery

It is important to ensure that the battery voltage is normal when testing various components. If required, a battery charger may be connected while testing.
The maximum permissible charging current is 15 A at 16 V.

- Do not disconnect leads when engine is running.
- Disconnect battery leads when booster charging.
- Do not use booster charger or apply voltage higher than 16 V when jump-starting.

Hygiene

Hygiene is particularly important when working on the transmission. Always use clean containers and keep the workplace free of dust and dirt.

Safe shop practices

Exercise due care during diagnosis and repair operations on the car. Especially when performing troubleshooting with freely rotating rear wheels. Use jack stands if the rear of the car is jacked for tests with freely rotating wheels. Keep the rear wheels clear of other persons.

Fluid grade

Use only the grades of fluid that complies with the specifications for both:

- Dexron llE and Ford Mercon alternatively
- Dexron lll and Ford Mercon