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

Refer to POWER STEERING CONTROLS for schematic and connector information.

Normal Operation and Fault Conditions 

REFER to: Power Steering - Overview .

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 

• 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 

• DTC Diagnostic Strategy 
• If the module DTC list results in a large number of DTC, 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 DTC are present, diagnose those after any module hard faults and before any network faults. Diagnose all current and active DTC before diagnosing any historic DTC.

Pinpoint Test Purpose 

• 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

• Ignition ON.

• Using a diagnostic scan tool, carry out a self-test of the module reporting DTC U0420:xx.

Is DTC U0420:xx currently present and active in the reporting module? 

• Ignition ON.

• Refer to PINPOINT TEST A: BATTERY CONDITION TEST and carry out Pinpoint Test A: Battery Condition Test (battery state of charge).

Did the battery pass the condition test (battery state of charge)? 

• Ignition ON.

• Using a diagnostic scan tool, carry out a self-test of the module reporting DTC U0420:xx.

Is DTC U0420:xx currently present and active in the reporting module? 

• Ignition OFF.

• Disconnect PSCM-A (or B) 3-pin and the in-line electrical connectors..

• Inspect all disconnected connectors for:
  • Pushed-out pins, loose pins, spread terminals, water ingress and corrosion.
  • Missing or loose latches, broken or cracked connector housings.
  • VDB wiring for pinched or cut wiring under brackets, air cleaner boxes, battery trays, engine pulleys, etc.

• Inspect the VDB wiring for pinched or cut wiring under brackets, air cleaner boxes, battery trays, engine pulleys, etc.

• Inspect the VDB wiring harness anchors for coming loose from anchoring locations in the engine compartment.

• Repair the connectors or wiring as necessary.

• Connect PSCM-A (or B) 3-pin and the in-line electrical connectors..

• Verify connectors are solidly latched and connected without water ingress gaps.

• Verify wiring harness anchors are solidly pushed into retaining holes, etc.

• Ignition ON.

• Using a diagnostic scan tool, clear all DTCs from the module reporting DTC U0420:xx.

• Ignition OFF.

• Ignition ON.

• Using a diagnostic scan tool, carry out a self-test of the module reporting DTC U0420:xx.

Is DTC U0420:xx currently present and active in the reporting module? 

• Ignition OFF.

• Disconnect GWM connector, C2431A .

• Disconnect PSCM_A connector, C1463A .

• Disconnect PSCM_B connector, C1463B .

• Disconnect the battery negative cable. REFER to: Battery - Vehicles With: Single Battery . REFER to: Battery - Vehicles With: Dual Batteries .

• Measure the resistance between:

  Positive Lead	Measurement / Action	Negative Lead
  C1463B-3	Courtesy of FORD MOTOR COMPANY	C2431A-8
  C1463B-2	Courtesy of FORD MOTOR COMPANY	C2431A-21

Are the resistances less than 3 ohms? 

• Connect PSCM_A connector, C1463A. Make sure the connector seats and latches correctly..

• Connect PSCM_B connector, C1463B. Make sure the connector seats and latches correctly..

• Connect GWM connector, C2431A. Make sure the connector seats and latches correctly..

• Connect the battery negative cable. REFER to: Battery - Vehicles With: Single Battery . REFER to: Battery - Vehicles With: Dual Batteries .

• Ignition ON.

• Using a diagnostic scan tool, clear all DTCs from the module reporting DTC U0420:xx.

• Ignition OFF.

• Operate the system.

• Using a diagnostic scan tool, clear all DTCs from the module reporting DTC U0420:xx.

Is DTC U0420:xx currently present and active in the reporting module?