U0001 Possible Causes

• Diagnosis of this diagnostic trouble code (DTC) is performed through vehicle symptoms
• Check for additional codes
• Faulty control module
• Control module harness is open or short-circuited
• Poor electrical connection in the control module circuit

How is U0001 Code Repaired?

Begin by checking the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated check engine light (or service engine soon warning light)

U0001 Meaning

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged between devices. Devices have programmed information about messages to exchange over serial data circuits. The CAN bus uses two dedicated wires for communication. The wires are called CAN high and CAN low. When the CAN bus is in sleep mode, both lines carry 2.5 V. When data bits are transmitted, the CAN high line rises to 3.75 V and the CAN low line drops to 1.25 V, thus generating a 2.5 V differential between the lines. Since communication relies on a voltage difference between the two bus lines, the CAN bus is NOT sensitive to inductive spikes, electric fields, or any other noise. The diagnostic trouble code (DTC) is set when a supervised periodic message including the transmitting device’s availability has not been received.

Organized Guide: Code U0001 FORD – Diagnosis and Repair

1. Overview of Code U0001

• Definition: Communication issue between the Power Steering Control Module (PSCM) and the HS-CAN (High-Speed Controller Area Network).
• Meaning:
  The PSCM detects a communication interruption with other modules on the HS-CAN network for more than 320 milliseconds, under the following conditions:
• Ignition on for more than 5 seconds.
• PSCM supply voltage > 9 volts.
• No other fault codes blocking PSCM operation.

2. Possible Causes

• PSCM module failure (faulty power steering control module).
• Electrical issues:
• PSCM wiring harness open circuit or shorted.
• Faulty electrical connection (loose connectors, corrosion, bent/damaged pins).

3. Common Symptoms

• Check engine light on (or “Service Engine Soon” message).
• Reduced or no power steering (depending on fault severity).
• Possible additional CAN communication-related codes.

4. Diagnostic Steps

A. Visual Inspection

1. Check PSCM wiring and connectors:

• Look for damaged, cut wires, or signs of corrosion.
• Inspect connectors for:
  • Bent, broken, or dislodged pins.
  • Presence of moisture or oxidation.

1. Check PSCM power supply voltage:

• Using a multimeter, verify voltage is > 9 volts (with ignition on).

B. Electrical Tests

1. Test circuit continuity:

• Check for no short circuit or break in the PSCM wiring harness.

1. HS-CAN network analysis:

• Use a diagnostic tool to verify communication between PSCM and other modules (e.g., ECM, ABS).
• Look for additional codes on the CAN network.

5. Repair Procedures

1. Fix connection issues:

• Clean or replace corroded connectors.
• Repair damaged wires or replace harness if necessary.

1. PSCM replacement:

• If the module is faulty (after eliminating electrical causes), replace it.
• Reset codes with a diagnostic tool after repair.

1. Software update:

• Check if a PSCM firmware update is available (via manufacturer diagnostic tool).

6. Technical Notes

• Recommended tools:
• Multimeter, oscilloscope (for CAN signal analysis), Ford-compatible diagnostic tool (e.g., Ford IDS/FDRS).
• Precautions:
• Disconnect the battery before any electrical work.
• Check fuses related to PSCM and CAN network.

Summary: Code U0001 on Ford indicates a communication problem between the PSCM and the CAN network. Repair involves thorough inspection of electrical circuits and connectors, followed by module replacement if necessary. A detailed HS-CAN network analysis is crucial to avoid unnecessary repairs.

U0002 Error Code: Possible Causes, Symptoms and Repair

Diagnosis of this diagnostic trouble code (DTC) is performed based on the symptoms presented by the vehicle. It is recommended to check if other error codes are also present.

Potential Causes:

• Faulty control module.
• Control module wiring harness open or shorted.
• Poor electrical connection in the control module circuit.

How to fix the U0002 code?

The first step is to carefully examine the “possible causes” mentioned above. Visually inspect the wiring harness and associated connectors. Look for any signs of damage to components and check the condition of the connector pins (broken, bent, pulled out, or corroded).

Possible Symptoms:

• The check engine light is on (or the “Service Engine Soon” light is displayed).

Meaning of Code U0002:

The Controller Area Network (CAN) communication network is an automotive bus standard designed to interconnect the various devices in a vehicle without requiring a central host computer. Operating information and commands are exchanged directly between these devices. Each device is programmed with information about the messages to be exchanged via the serial data circuits.

The CAN bus uses two wires dedicated to communication, called CAN High and CAN Low. When the CAN bus is in sleep mode, both lines maintain a voltage of 2.5 V. When transmitting data bits, the CAN High line rises to 3.75 V while the CAN Low line drops to 1.25 V, thus creating a potential difference of 2.5 V between the two lines. Thanks to this communication method based on voltage difference, the CAN bus is immune to inductive spikes, electric fields, and any other type of noise.

The diagnostic trouble code (DTC) U0002 is set when a periodic supervision message, indicating the availability of the transmitting device, has not been received by the system.

U0003 Possible Causes

• Diagnosis of this diagnostic trouble code (DTC) is performed through vehicle symptoms
• Check for more codes
• Faulty control module
• Control module harness is open or shorted
• Poor electrical connection in control module circuit

How is U0003 Code Repaired?

Begin by checking the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Engine light on (or service engine soon warning light)

U0003 Meaning

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged between devices. Devices have programmed information about messages to exchange on serial data circuits. The CAN bus uses two dedicated wires for communication. The wires are called CAN high and CAN low. When the CAN bus is in sleep mode, both lines carry 2.5 V. When data bits are transmitted, the CAN high line rises to 3.75 V and the CAN low line drops to 1.25 V, thus generating a 2.5 V differential between the lines. Since communication relies on a voltage difference between the two bus lines, the CAN bus is NOT sensitive to inductive spikes, electric fields, or any other noise. The diagnostic trouble code (DTC) is set when a supervised periodic message including the transmitting device’s availability has not been received.
U0003 More Information

U0004 Possible Causes

• Diagnosis of this diagnostic trouble code (DTC) is performed through vehicle symptoms
• Check for additional codes
• Faulty control module
• Control module harness is open or shorted
• Poor electrical connection in control module circuit

How is U0004 Code Repaired?

Begin by checking the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated check engine light (or service engine soon warning light)

U0004 Meaning

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged between devices. Devices have programmed information about messages to exchange on serial data circuits. The CAN bus uses two dedicated wires for communication. The wires are called CAN high and CAN low. When the CAN bus is in sleep mode, both lines carry 2.5 V. When data bits are transmitted, the CAN high line rises to 3.75 V and the CAN low line drops to 1.25 V, thus generating a 2.5 V differential between the lines. Since communication relies on a voltage difference between the two bus lines, the CAN bus is NOT sensitive to inductive spikes, electric fields, or any other noise. The diagnostic trouble code (DTC) is set when a supervised periodic message including transmitter device availability has not been received.

U0004 FORD Possible Causes

• Diagnosis of this diagnostic trouble code (DTC) is performed via vehicle symptoms
• Check for more codes
• Faulty control module
• Control module harness is open or shorted
• Poor electrical connection in control module circuit

How is FORD U0004 Code Repaired?

Begin by checking the “Possible Causes” listed above. Visually inspect the wiring harness and associated connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Check engine light illuminated (or service engine soon warning light)

U0004 FORD Meaning

Multiplexing is a method of simultaneously sending 2 or more signals over the same circuit. Multiplexing allows 2 or more electronic modules (nodes) to communicate over a twisted pair network [data (+) and data (-)]. The information or messages that can be communicated over these wires consist of commands, status, or data. Multiplexing reduces vehicle weight by decreasing the number of redundant components and electrical wiring. The vehicle has 4 module communication networks connected to the DLC, located under the dashboard. The communication networks are: High Speed Controller Area Network HEV (HS-CAN), High Speed Controller Area Network (HS-CAN), Medium Speed Controller Area Network (MS-CAN), and Infotainment Controller Area Network (I-CAN). Diagnostic trouble code (DTC) U0004 is set when a failure in the High Speed Controller Area Network (HS-CAN) was present at some point. The fault is not present because the module communicates with the scan tool

U0005 Possible Causes

• Diagnosis of this diagnostic trouble code (DTC) is performed through vehicle symptoms
• Check for additional codes
• Faulty control module
• Control module harness is open or shorted
• Poor electrical connection in control module circuit

How is U0005 Code Repaired?

Begin by checking the “Possible Causes” listed above. Visually inspect the wiring harness and associated connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated check engine light (or service engine soon warning light)

U0005 Meaning

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged between devices. Devices have programmed information about messages to exchange on serial data circuits. The CAN bus uses two dedicated wires for communication. The wires are called CAN high and CAN low. When the CAN bus is in sleep mode, both lines carry 2.5 V. When data bits are transmitted, the CAN high line rises to 3.75 V and the CAN low line drops to 1.25 V, thus generating a 2.5 V differential between the lines. Since communication relies on a voltage difference between the two bus lines, the CAN bus is NOT susceptible to inductive spikes, electric fields, or any other noise. The diagnostic trouble code (DTC) is set when a supervised periodic message including the transmitting device’s availability has not been received.