Pinpoint Test Bl: DTC (Diagnostic Trouble Code) U0420:XX Invalid Data Received From The PSCM (Power Steering Control Module)

WARNING: This page is about a different car, the 2021 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.

Refer to Power Steering Controls for schematic and connector information.

Normal Operation and Fault Conditions

REFER to: Power Steering - System Operation and Component Description .

Description

The PSCM receives messages from other modules through 2 connectors: the PSCM-A (or B) 3-pin connector at the gear and the multi-pin in-line connector in the engine compartment. The in-line connector receives messages from the other modules into the PSCM wiring harness. The PSCM wiring harness uses the VDB wiring to carry the messages from the in-line connector to the PSCM-A (or B) 3-pin connector. If any of the connector pins or VDB communication wires are loose or damaged, the PSCM cannot properly receive messages from other modules.

Pinpoint Test Applicability

This test applies to DTC U0420:xx Invalid Data Received from the Power Steering Control Module, and is set by other modules. It DOES NOT apply to any other DTC.

DTC Diagnostic Strategy

If the module DTC list results in a large number of Diagnostic Trouble Codes (DTCs), diagnose all module hard faults first (C102D, C1B00, C200B, C200C, C200D, U2011 and U3000) before diagnosing any network faults (lost communication or invalid data). If voltage concern Diagnostic Trouble Codes (DTCs) are present, diagnose those after any module hard faults and before any network faults. Diagnose all current and active Diagnostic Trouble Codes (DTCs) before diagnosing any historic Diagnostic Trouble Codes (DTCs).

Pinpoint Test Purpose

To verify the condition of the battery state of charge, the PSCM wiring harness and electrical connectors. The test checks battery state of charge and checks the connectors and wiring from the PSCM 3-pin connector at the PSCM to the in-line connector in the passenger compartment.

Possible Sources

Fuse
Wiring, terminals or connectors
Network communication concern
12-volt battery
Charging system concern
Module internal failure

Pinpoint Tests BL: DTC U0420 Invalid Data Received From The PSCM