Component Tests and General Diagnostics

Checking The Supply Voltage/ground Terminal

Checking the power supply and ground terminals

CAUTION: Do not touch the terminal pins in the supplemental restraint system module (SRS). There is a risk of static discharge which could damage the control module.

Power supply, supplemental restraint system module (SRS)

The supplemental restraint system module (SRS) is powered via two power inputs.

When the ignition is switched on, at least one of the power inputs is powered and the supplemental restraint system module (SRS) is in active mode.

1. Power input 1 terminal #55 is X-supplied via the ignition switch when it is in positions I and II. This power input is used to supply power to the supplemental restraint system module (SRS)

2. Power input 2 terminal #56 is supplied with +15 via the ignition switch when it is in positions II and III. This power input is used to power the supplemental restraint system module (SRS).

The two independent power supplies are used to facilitate supply of power to the supplemental restraint system module (SRS) for longer in the event of a collision. In the event of simultaneous open-circuits in both power supplies, the supplemental restraint system module (SRS) will not be active.

Checking the power supply

Check the power supply cable from the battery to the ignition switch. Check for an open-circuit. Check for loose connections. Check for contact resistance. Check for oxidation. Check the fuse.

Check the power supply cables from the ignition switch to supplemental restraint system module (SRS) terminals #55 and #56. Check for an open-circuit. Check for loose connections. Check for contact resistance. Check for oxidation.

- The voltage to terminal #55 must be approximately battery voltage when the ignition is in positions I and II

- The voltage to terminal #56 must be approximately battery voltage when the ignition is in positions II and III.

Ground terminal, supplemental restraint system module (SRS)

The supplemental restraint system module (SRS) is grounded when it is screwed into place in the car.

Checking the ground terminal

Check the ground connection between the supplemental restraint system module (SRS) and the ground terminal. Check for resistance. With the ignition off and the supplemental restraint system module (SRS) installed in the vehicle, the resistance measurement between the supplemental restraint system module (SRS) and the ground terminal must be approximately 0 ohms.

Take readings between the metal casing on the supplemental restraint system module (SRS) and the ground terminal.

Remedy as necessary.

Other information
- Connecting the breakout box
- Signal specification
- Wiring harness supplemental restraint system (SRS)
- Checking wiring and terminals.