LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Cadillac >> 2003 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 647 (Navigation Systems) >> Diagnostic Information and Procedures >> DTC B0001: PCM Discrete Input Speed Signal Error >> Test Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test Description

WARNING: This page is about a different car, the 2004 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 1:  Determines if the malfunction is present.
  2. 3:  Tests for an open in the vehicle speed signal circuit between the instrument cluster and the navigation radio. A short would cause the instrument cluster to malfunction as well as the navigation system.
DTC B0001

Step Action Yes No
Schematic Reference: Navigation System Schematics 
Connector End View Reference: Entertainment Connector End Views
Did you perform Diagnostic System Check - Navigation System  ? Go to Step 2  Go Diagnostic System Check - Navigation System 
2 Verify the instrument cluster speedometer operation.
Does the speedometer work on the instrument cluster?
Go to Step 3  Go to Diagnostic System Check - Instrument Cluster
Test the vehicle speed signal circuit for an open between the instrument cluster and the navigation radio. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 6  Go to Step 4 
4 Inspect for poor connections at the harness connector of the navigation radio. 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 6  Go to Step 5 
5 Replace the navigation radio. Refer to Radio Replacement in Entertainment.
Did you complete the replacement?
Go to Step 6  -
6
  1. Use the scan tool in order to clear the DTC.
  2. Drive the vehicle at least 4 km (2.5 mi) with the GPS signal received.
  3. Leave vehicle running and retrieve DTCs.
Does the DTC reset?
Go to Step 2  System OK