Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: OnStar Schematics DEFINITION: When the OnStar® call button is pressed, the audio prompt "Connecting to OnStar®" or "Unable to contact OnStar®" will play and no connection is made. | ||||
1 | Did you perform the Cellular Communication Diagnostic System Check? | -- | Go to Step 2 | Go to OnStar System Check |
2 |
Does the green LED flash? | -- | Go to Step 3 | |
3 | Did you connect to the OnStar® Call Center? | -- | Go to Step 23 | Go to Step 4 |
4 | Is a fast busy beep heard? | -- | Go to Step 5 | Go to Step 6 |
5 | Test the operation of the OCC and emergency button. Allow at least 3 minutes for each call to complete. Did you connect to the OnStar® Call Center? | -- | Go to Step 23 | Go to Step 7 |
6 | Are any cellular messages heard? | -- | Record all cellular messages and call the OnStar Technical Assistance Center | Go to Step 7 |
7 | Inspect for poor connections at the cellular coax connection of the Vehicle Communications Unit (VCU) and cellular antenna base. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 23 | Go to Step 8 |
8 | Test the cellular coax for high resistance.
Does the resistance measure near the specified value? | Less than 1ohms | Go to Step 9 | Go to Step 10 |
9 | Test for continuity between the cellular coax center conductor and the coax outer metal shield. Is continuity present? | -- | Go to Step 10 | Go to Step 11 |
10 | Replace the cellular coax cable. Did you complete the replacement? | -- | Go to Step 23 | -- |
11 |
Does the voltage measure near the specified value? | 0 V | Go to Step 12 | Go to Step 13 |
12 | Measure the voltage from the OnStar® transceiver (XCVR) CMP circuit and a good ground. Does the voltage measure near the specified value? | 5 V | Go to Step 14 | Go to Step 15 |
13 | Test the OnStar® transceiver (XCVR) RTN circuit for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 23 | Go to Step 16 |
14 | Measure the voltage from the OnStar® transceiver (XCVR) CMP circuit and the transceiver low reference circuit. Does the voltage measure near the specified value? | 5 V | Go to Step 17 | Go to Step 18 |
15 | Test the OnStar® transceiver (XCVR) CMP circuit for an open or short. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 23 | Go to Step 16 |
16 | Inspect for poor connections at the harness connector of the Vehicle Interface Unit (VIU). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 23 | Go to Step 19 |
17 | Measure the voltage from the OnStar® transceiver (XCVR) TRU circuit and a good ground. Does the voltage measure near the specified value? | 5 V | Go to Step 20 | Go to Step 21 |
18 | Test the transceiver (XCVR DIG) low reference circuit for an open or short. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 23 | Go to Step 16 |
19 | Replace the VIU. Refer to OnStar Vehicle Interface Unit Replacement . Did you complete the replacement? | -- | Go to Step 23 | -- |
20 | Inspect for poor connections at the harness connector of the VCU. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 23 | Go to Step 22 |
21 | Test the OnStar® transceiver (XCVR) TRU circuit for an open or short. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 23 | Go to Step 16 |
22 | Replace the VCU. Refer to OnStar Vehicle Communication Unit Replacement . Did you complete the replacement? | -- | Go to Step 23 | -- |
23 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 |
