Pinpoint Test N: Abs (Anti-Lock Brake System) Module Communication Concern With The Pcm (Powertrain Control Module) / TCM (Transmission Control Module)
- Refer to Horn/Cigar Lighter
for schematic and connector information.
Normal Operation and Fault Conditions
On vehicles equipped with a 3.5L engine, the TCS in an internal part of the PCM. With the ignition ON, the PCM sends messages to the ABS module over the HS-CAN. If the ABS module does not receive these messages within the specified time frame, the ABS module sets DTCs. This can be due to a PCM failure, a circuit failure on the HS-CAN or an excessive load on the network.
The CCM is an internal component of the PCM. With the ignition ON, the PCM sends messages to the ABS module through the BCM over the HS-CAN. If the ABS module does not receive these messages within the specified time frame, the module sets a DTC. This can be due to a PCM failure, a circuit failure on the HS-CAN or an excessive load on the network.
For information on the messages sent to the ABS module by the PCM, REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description . .
The stoplamp switch (also known as the brake pedal switch, BPP switch and BOO switch) contains 2 sets of contacts, one set for a voltage signal and the other set for a ground signal.
For the voltage signal input, the stoplamp switch receives voltage at all times from the BCM. When the brake pedal is applied, the normally open switch closes and routes voltage to the BCM and the PCM.
For the ground signal input, the stoplamp switch receives a voltage signal from the PCM. The voltage signal is routed to ground through the normally closed switch. When the brake pedal is applied, the normally closed switch opens, interrupting the voltage signal from the PCM.
When the PCM receives these inputs it sends a message on the HS-CAN to the ABS module and other modules.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition ABS U0401:83 Invalid Data Received from ECM/PCM A: Value Of Signal Protection Calculation Incorrect This DTC sets when the ABS module receives Incorrect Value Of Signal Protection Calculation from PCM ABS U0401:82 Invalid Data Received from ECM/PCM A: Alive/Sequence Counter Incorrect/Not Updated Sets when the ABS module detects the cruise control status counter message does not increase following a cruise control event. ABS U0100:00 Lost Communication With ECM/PCM "A": No Sub Type Information This DTC sets when the ABS module does not receive any messages from the PCM within the allowed time. ABS U0401:86 Invalid Data Received from ECM/PCM A: Signal Invalid This DTC sets when the ABS module receives invalid data in the accelerator pedal message. ABS U0402:00 Invalid Data Received from TCM: No Sub Type Information Sets when the ABS module receives any invalid data from the PCM. ABS U0101:00 Lost Communication with TCM: No Sub Type Information Sets when the ABS module does not receive any transmission messages from the PCM. Possible Sources
- Network communication concern
- Battery or charging system concerns
- Stoplamp switch
- PCM
- ABS module
- N1 CHECK THE COMMUNICATION NETWORK
- Ignition ON.
- Retrieve DTCs from the vehicle. NOTE: DTCs may be displayed from previous diagnostic actions.
Does the PCM pass the Network Test?
Yes GO to N2 No DIAGNOSE the PCM does not communicate with the diagnostic scan tool. - N2 RECHECK FOR DTC (DIAGNOSTIC TROUBLE CODE) C0040:64
- Carry out the ABS self-test.
- Clear the ABS DTCs.
- Ignition OFF.
- Ignition ON.
- Carry out the ABS self-test.
- Record all retrieved ABS module DTCs.
Is DTC C0040:64 retrieved again?
Yes GO to Pinpoint Test AK No If no DTCs are present, the system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition. If DTC U0100:xx, U0101:xx, U0401:xx, or U0402:xx is present, GO to N3. - N3 REVIEW THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE SELF-TEST FOR VOLTAGE-RELATED DTC (DIAGNOSTIC TROUBLE CODE) S
- Review the recorded DTCs from the ABS self-test.
Is DTC U3003:16 or U3003:17 present?
Yes For DTC U3003:16, GO to Pinpoint Test A For DTC U3003:17, GO to Pinpoint Test D No GO to N4 - N4 CHECK FOR PCM (POWERTRAIN CONTROL MODULE) DTC (DIAGNOSTIC TROUBLE CODE) S
- Carry out the PCM KOEO self-test.
Are any DTCs present?
Yes For EcoBoost, DIAGNOSE the PCM DTC. For Duratec, DIAGNOSE the PCM DTC. No GO to N5 - N5 CHECK FOR OTHER CAUSES OF COMMUNICATION NETWORK CONCERNNOTE: If new modules were installed prior to the DTC being set, the module configuration can be incorrectly set during the PMI or the PMI may not have been carried out.
- Check the vehicle service history for recent service actions related to the PCM or the ABS module. If recent service history is found:
- Verify the correct replacement module was installed. HVBOM may be used to verify correct part fitment.
- Verify the configuration of replacement module was correct. Re-configure the module using as-built data if prior configuration is suspect.
- Verify the module was not obtained from a like vehicle and installed into customer vehicle. Return the swapped module to source vehicle and obtain new replacement module.
- Operate the system and determine if the observable symptom is still present.
Is the observable symptom still present?
Yes GO to N6 No The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration. - Check the vehicle service history for recent service actions related to the PCM or the ABS module. If recent service history is found:
- N6 CHECK FOR LOST COMMUNICATION DTC (DIAGNOSTIC TROUBLE CODE) SET IN OTHER MODULES
- Retrieve DTCs from the vehicle. NOTE: DTCs may be displayed from previous diagnostic actions.
Is DTC C0040:64, U0100:xx, U0101:xx, U0104:xx, U0401:xx, or U0402:xx set in 1 or more modules in addition to the ABS module?
Yes DIAGNOSE the PCM communications fault For EcoBoost, For Duratec, No GO to N7 - N7 CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OPERATION
- Ignition OFF.
- Disconnect ABS module connector, C135. If not previously disconnected.
- Using a good light source, inspect all disconnected electrical connectors for the following:
- Corrosion - install new connector or terminal and clean the module pins
- Damaged or bent pins - install new terminals or pins
- Pushed-out pins - install new pins as necessary
- Spread terminals - install new terminals as necessary
- Reconnect the ABS module connector. Make sure it seats and latches correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no services articles address this concern, INSTALL a new ABS module. REFER to: Anti-Lock Brake System (ABS) Module
ORDER a replacement ABS module and INCLUDE the RVC on the form. If this is a Ford paid repair, INCLUDE the RVC on the warranty claim form.No The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.