Circuit Description
The compass display is part of the driver information center (DIC) within the instrument panel cluster (IPC). The IPC and the electronic compass module communicate on a 2-wire serial peripheral interface (SPI). The IPC controls the compass clock signal circuit which is used for the communication timing between the IPC and the electronic compass module. The compass information is transmitted on the bi-directional compass data signal circuit. The SPI is idle when the compass clock signal circuit is high and the compass data signal circuit is low.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC U1450 Lost Communications With Compass
Conditions for Running the DTC
| • | The ignition is ON. |
| • | B1327 is not set. |
Conditions for Setting the DTC
The IPC does not detect the electronic compass module for greater than 4 seconds.
Action Taken When the DTC Sets
The compass display is blank.
Conditions for Clearing the DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 50 malfunction-free ignition cycles. |
| • | The IPC receives a clear code command from the scan tool. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Instrument Cluster Schematics | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 | Turn ON the ignition, with the engine OFF. Does the compass operate properly? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
3 |
Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 13 |
4 | Connect a test lamp between the ignition 3 voltage circuit and the ground circuit of the electronic compass module. Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 14 |
5 | Measure the voltage between the compass clock signal circuit and a good ground. Does the voltage measure greater than the specified value? | 9 V | Go to Step 6 | Go to Step 7 |
6 | Measure the voltage between the compass data signal circuit and a good ground. Does the voltage measure less than the specified value? | 3 V | Go to Step 8 | Go to Step 10 |
7 | Test the compass clock signal circuit for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 12 |
8 | Test the compass clock signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 9 |
9 | Test the compass data signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 11 |
10 | Test the compass data signal circuit for an open, a high resistance, or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 11 |
11 | Inspect for poor connections at the harness connector of the electronic compass module. 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 17 | Go to Step 15 |
12 | Inspect for poor connections at the harness connector of the instrument panel cluster (IPC). 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 17 | Go to Step 16 |
13 | Repair the short to ground, the open, or the high resistance in the ignition 3 voltage circuit of the electronic compass module. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 17 | -- |
14 | Repair the open or the high resistance in the ground circuit of the electronic compass module. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 17 | -- |
15 |
Important: Perform the calibration and variance procedure for the replacement electronic compass module. Replace the electronic compass module. Refer to Electronic Compass Module Replacement . Did you complete the replacement? | -- | Go to Step 17 | -- |
16 | Replace the IPC. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 17 | -- |
17 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
