Chart G DERM Cannot Communicate With Scan Tool

DESCRIPTION
When Ignition Switch is first turned "ON" system voltage is applied through Fuse #6 to "Redundant indicator Ignition t" input (B2) and "INFLATABLE RESTRAINT" warning lamp which is connected to "SIR Indicator" output (B1). Fuse #7 also applies system voltage to "IGNITION 1" inputs (A9 and A10). DERM responds by blinking "INFLATABLE RESTRAINT" warning lamp 7 times.

When engine is being cranked, system voltage is applied to DERM at "CRANK" input (B10). DERM grounds lamp circuit until system voltage is removed from "CRANK" input (B10). This results in a steady "INFLATABLE RESTRAINT" warning lamp during cranking.

After cranking DERM again blinks "INFLATABLE RESTRAINT" warning lamp 7 times, with solid "ON" of indicator during "CRANK" counting as one.

NOTES ON FAULT TREE
1. An improper connection to DLC prevents communications from being established.
2. The correct "Body Systems" cartridge must be used.
3. This checks "Data Link" circuit for proper voltage. An open, short to ground or short to voltage in any wire or component attached to this circuit causes scan tool communications to fail.
4. This test checks for a short to ground on "Data Link" circuit between DERM and DLC.
5. This test checks for an open in "Data Link" circuit between DERM and DLC.
6. This test checks for a short to voltage on "Data Link" circuit between DERM and DLC.
7. This test checks for proper terminal contact in "Data Link" circuit at DERM and DLCs. Refer to "Intermittents and Poor Connections" to properly check terminals. Intermittent Problems