U1A00:49
Anti-Lock Control
Pinpoint Test M: DTCs U1A00:49 and U1A00:87
Normal Operation
The Restraints Control Module (RCM) measures vehicle yaw rate and lateral acceleration and sends the information to the ABS module along a dedicated Controller Area Network (CAN). This dedicated CAN (Controller Area Network) is used only for communication between the RCM (Restraints Control Module) and the ABS module. The yaw rate sensor lateral accelerometer are contained in the RCM (Restraints Control Module).
- DTC U1A00:49 (Private Communication Network: Internal Electronic Failure)- sets in continuous memory when there is a communication issue between the ABS module and the RCM (Restraints Control Module).
- DTC U1A00:87 (Private Communication Network: Missing Message)- sets in continuous memory when expected messages such as yaw rate sensor and lateral accelerometer are missing for more than 5 seconds.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals, or connectors
- RCM (Restraints Control Module)
- ABS module
PINPOINT TEST M : DTC U1A00:49 AND U1A00:87
WARNING: Never probe the electrical connectors on air bag, Safety Canopy(R) or side air curtain modules. Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
M1 CHECK FOR AN HS-CAN (High Speed Controller Area Network) CONCERN WITH THE RCM (Restraints Control Module)
- NOTE: The network test does not test the dedicated CAN (Controller Area Network) communications between the ABS module and RCM (Restraints Control Module).
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Network Test.
Does the RCM (Restraints Control Module) pass the network test?
Yes
GO to M2.
No
REFER to Information Bus to diagnose the RCM (Restraints Control Module) does not respond to the scan tool.
M2 VERIFY THE RCM (Restraints Control Module) PART NUMBER
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Log Viewer.
- Retrieve and record the RCM (Restraints Control Module) part number from the log viewer.
- Check the part number recorded against the number listed in the Ford Catalog Advantage(TM) or equivalent.
Does the part number on the RCM (Restraints Control Module) match the part number listed in the Ford Catalog Advantage(TM) or equivalent?
Yes
GO to M3.
No
INSTALL the correct RCM (Restraints Control Module). CLEAR the DTCs. REPEAT the self-test.
M3 CHECK THE DEDICATED CAN (Controller Area Network) CIRCUITS FOR A SHORT TO VOLTAGE
- Depower the Supplemental Restraint System (SRS). Refer to Restraints and Safety Systems &/or Air Bag Systems.
- Disconnect: RCM (Restraints Control Module) C2041B.
- Disconnect: ABS Module C135.
- Connect: Negative Battery Cable.
- Ignition ON.
- Measure the voltage between ground and:
- ABS module C135-9, circuit VCA24 (GN/OG), harness side.
- ABS module C135-8, circuit VCA23 (BU/WH), harness side.
Is any voltage present?
Yes
REPAIR the affected circuit(s) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
No
GO to M4.
M4 CHECK THE DEDICATED CAN (Controller Area Network) CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the ABS module C135, harness side and ground:
- ABS module C135-9, circuit VCA24 (GN/OG), harness side.
- ABS module C135-8, circuit VCA23 (BU/WH), harness side.
Are the resistances greater than 10,000 ohms?
Yes
GO to M5.
No
REPAIR the affected circuit(s). TEST the system for normal operation.
M5 CHECK THE DEDICATED CAN (Controller Area Network) CIRCUITS FOR A SHORT TOGETHER
- Measure the resistance between ABS module C135-9, circuit VCA24 (GN/OG), harness side and ABS module C135-8, circuit VCA23 (BU/WH), harness side.
Is the resistance greater than 10,000 ohms?
Yes
GO to M6.
No
REPAIR the circuits. CLEAR the DTCs. REPEAT the self-test.
M6 CHECK THE DEDICATED CAN (Controller Area Network) CIRCUITS FOR AN OPEN
- Measure the resistance between the ABS module C135, harness side and the RCM (Restraints Control Module) C2041B, harness side as follows:
ABS Module Circuit RCM (Restraints Control Module) C135-8 VCA23 (BU/WH) C2041B-20 C135-9 VCA24 (GN/OG) C2041B-19
Are the resistances less than 5 ohms?
Yes
GO to M7.
No
REPAIR the affected circuit(s). CLEAR the DTCs. CYCLE the ignition key. REPEAT the self-test.
M7 CHECK FOR CORRECT RCM (Restraints Control Module) OPERATION
- Disconnect: RCM (Restraints Control Module).
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect: RCM (Restraints Control Module).
- Make sure the connectors are seated correctly.
- Repower the SRS (Supplemental Restraint System). Refer to Restraints and Safety Systems &/or Air Bag Systems.
- Operate the system, verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new RCM (Restraints Control Module). CLEAR the DTCs. REPEAT the self-test.
If DTCs U1A00:49 and U1A00:87 are retrieved again, GO to M8.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
M8 CHECK FOR CORRECT ABS MODULE OPERATION
- Disconnect: ABS Module.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect: ABS Module.
- Make sure the connector is seated correctly, then operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module . TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.