Need ABS Module wiring pin out

Look at the transmission control module. Sounds like a massive wiring harness problem too.

Kim, CODE U1418 The ABS Module sends an implausible distance signal over the CAN C Bus circuit to the PCM

• POSSIBLE CAUSES
• VEHICLE SPEED SENSOR FAULT ACTIVE IN ANTI-LOCK BRAKE MODULE
• ,CAN C BUS CIRCUIT SHORTED
• CAN C BUS CIRCUIT OPEN
• ABS MODULE
• PCM.

I recommend you take it in to reputable shop.
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."

ABS and traction control both use the wheel speed sensors and are controlled through the same module . What resistance readings did you get ? Did you test AC voltage with the wheel spinning ?

You need to find out what code is stored in the ABS control module, if the light is on there is a DTC an the system is disabled ! Don't know if auto part stores can pull ABS codes or not , You'll have to check it out . Personally I say take it to a ASE certified repair shop if you don't know anything about anti lock brakes !
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Electronic Brake Control Module (EBCM) -- The EBCM controls the system functions and detects failures.

The EBCM contains the following components:

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System Relays -- The inlet and outlet solenoid relay is energized when the ignition is ON and no ABS DTCs are present. It supplies battery positive voltage to the solenoid valves, the pump motor relay is energized and supplies battery positive voltage to the pump motor when ABS is activated.

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Brake Pressure Modulator Valve (BPMV) -- The BPMV contains the hydraulic valves and pump motor that are controlled electrically by the EBCM. The BPMV uses a 4 circuit configuration with a diagonal split. The BPMV directs fluid from the reservoir of the master cylinder to the left front and right rear wheels and fluid from the other reservoir to the right front and left rear wheels. The diagonal circuits are hydraulically isolated so that a leak or malfunction in one circuit will allow continued braking ability on the other.

This system can store 10-12 DTC's for something simple as wheel speed sensors to wiring problems to a malfunction of the EBCM . Some of these problems you would need a professional type scan tool ! The antilock brake system on your vehicle is the
BOSCH 8.0 antilock braking system
The vehicle is equipped with the following braking systems:
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Antilock Brake System (ABS)

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Dynamic Rear Proportioning (DRP)

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Traction Control System (TCS) (w/NW7)

The following components are involved in the operation of the above systems:
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Electronic Brake Control Module (EBCM) -- The EBCM controls the system functions and detects failures.

The EBCM contains the following components:

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System Relays -- The inlet and outlet solenoid relay is energized when the ignition is ON and no ABS DTCs are present. It supplies battery positive voltage to the solenoid valves, the pump motor relay is energized and supplies battery positive voltage to the pump motor when ABS is activated.

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Brake Pressure Modulator Valve (BPMV) -- The BPMV contains the hydraulic valves and pump motor that are controlled electrically by the EBCM. The BPMV uses a 4 circuit configuration with a diagonal split. The BPMV directs fluid from the reservoir of the master cylinder to the left front and right rear wheels and fluid from the other reservoir to the right front and left rear wheels. The diagonal circuits are hydraulically isolated so that a leak or malfunction in one circuit will allow continued braking ability on the other.

Important: There is a rubber isolator located under the BPMV and on the mounting studs. The rubber isolators protect the BPMV and the EBCM from vehicle vibrations.

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The BPMV contains the following components:

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Pump Motor

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Inlet Valves (one per wheel)

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Outlet Valves (one per wheel)

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Wheel Speed Sensors (WSS) -- As the wheel spins, the wheel speed sensor produces an AC signal. The EBCM uses this alternating current signal to calculate wheel speed. The wheel speed sensors are replaceable only as part of the wheel hub and bearing assemblies.

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Traction Control Switch (w/NW7) -- The TCS is manually disabled or enabled using the traction control switch.

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Stop Lamp Switch - The EBCM uses the stop lamp switch as an indication that the brake pedal is applied

Error logs are a great thing. They will help you find intermittent problems and start you off in a general direction of where a problem could be. There is a great level of detail on the justcommodores site on checking error codes logged by the engine management system, but this does not detail anything about the abs system. The abs warning light is not as common as the check engine warning light. Reading through the posts, I haven't found any detail on checking error codes logged by the abs system.

So here it is. For those of you familiar with checking the engine error codes, this procedure is so simple its not funny.

Basically, to check the engine error log, you bridge the 5th (ground) and 6th pins in the ODB connector under the steering wheel.

To check the ABS error log, using the same trusty calibrated paper clip, you simply bridge pins 5 and 12 of the connector.

To find pins 5 and 12, start at the top left hand corner. That is pin one. Going to the right, you count pin 2,3,4 etc. Once you get to the end, jump back to the start of the bottom left level of pins and keep counting. Pin 5 is about halfway along the top row, pin 12 is a little left of the middle in the bottom row.

Reading the error codes is the same procedure (counting the flashes), except now, the ABS light flashes (as opposed to the engine light when checking the engine codes).

The ABS log also uses code 12 firstly, with any errors logged shown after that. If no errors are logged, the 12 will flash again.

Error codes for the ABS error log (VR/VS) are as follows:

12 Diagnostic system operational
21 Right hand front wheel speed sensor fault
23 Right hand front wheel speed sensor continuity fault
25 Left hand front wheel speed sensor fault
27 Left hand front wheel speed sensor continuity fault
28 Wheel speed sensor frequency error
31 Right hand rear wheel speed sensor fault
33 Right hand rear wheel speed sensor continuity fault
35 Left hand rear wheel speed sensor fault
37 Left hand rear wheel speed sensor continuity fault
41 Right hand front inlet solenoid valve circuit fault
42 Right hand front outlet solenoid valve circuit fault
45 Left hand front inlet solenoid valve circuit fault
46 Left hand front outlet solenoid valve circuit fault
55 Rear inlet solenoid valve circuit fault
56 Rear outlet solenoid valve circuit fault
61 Pump motor relay circuit fault
63 Valve relay circuit fault
71 ABS control module internal fault

The above guide has been verified on a VR/VS. Checking the error log on all models prior to VR/VS is the same for the engine log, and I would assume that the same can be said for the ABS log, would be happy if someone could verify this for me.

Having the vehicle checked for DTC'S - diagnostic trouble code's would be a good first step . ABS light on codes are stored . Suggest you take your vehicle to a qualified repair shop that has the knowledge an testing equipment to diagnose the problem properly .
Anti-Lock Brake System (ABS)
The 4-wheel, 4-channel anti-lock brake system (ABS) consists of the following components:

• ABS module
• Front wheel speed sensor
• Front wheel speed sensor ring (integral to the front wheel bearing)
• Hydraulic control unit (HCU)
• Rear wheel speed sensor
• Rear wheel speed sensor ring (integral to the rear halfshaft)
• Yellow ABS warning indicator
• As you can see here , it can set numerous
• DTC'S Why guess an replace parts that won't fix the problem .
• Anti-Lock Brake System (ABS) Module Diagnostic Trouble Code (DTC) Index DTC Description Source Action B1342 ECU is Faulted ABS Module NOTE: If other DTCs are present, REPAIR them before installing a new component.
  CLEAR the DTCs. RETRIEVE the DTCs. If DTC B1342 is retrieved, INSTALL a new module. REFER to Anti-Lock Brake System (ABS) Module in this section. REPEAT the self-test. B1483 Brake Pedal Input Circuit Failure ABS Module Go To Pinpoint Test B . B1676 Battery Pack Voltage Out of Range ABS Module Go To Pinpoint Test C . B2477 Module Configuration Failure ABS Module CONFIGURE the ABS module. REFER to Section 418-01 . CLEAR the DTCs. REPEAT the self-test. If DTC B2477 is retrieved again, INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module . REPEAT the self-test. B2734 Pedal Travel Sensor Supply Error ABS Module Go To Pinpoint Test M . B2736 Pedal Travel Sensor Circuit Fault ABS Module Go To Pinpoint Test M . B2737 Pedal Travel Sensor Jammed Error ABS Module Go To Pinpoint Test M . B2738 Pedal Travel Sensor Velocity Error ABS Module Go To Pinpoint Test M . B2740 Pedal Travel Sensor Spike Error ABS Module Go To Pinpoint Test M . B2741 Sensor Cluster Defective ABS Module FOLLOW the diagnostic tool directions for the calibration procedure. B2900 VIN Mismatch ABS Module VERIFY that the module has the correct as-built data.
  CHECK for correct powertrain control module (PCM) and ABS module configurations using the diagnostic tool. RECONFIGURE the component as necessary. FOLLOW the diagnostic tool directions for the ABS module configuration or REFER to Section 418-01 for the PCM. CLEAR the DTC. REPEAT the self-test. C1095 ABS Hydraulic Pump Motor Circuit Failure ABS Module Go To Pinpoint Test D . C1145 Speed Wheel Sensor RF Input Circuit Failure ABS Module Go To Pinpoint Test E . C1155 Speed Wheel Sensor LF Input Circuit Failure ABS Module Go To Pinpoint Test E . C1165 Speed Wheel Sensor RR Input Circuit Failure ABS Module Go To Pinpoint Test E . C1175 Speed Wheel Sensor LR Input Circuit Failure ABS Module Go To Pinpoint Test E . C1233 Speed Wheel LF Input Signal Missing ABS Module Go To Pinpoint Test F . C1234 Speed Wheel RF Input Signal Missing ABS Module Go To Pinpoint Test F . C1235 Speed Wheel RR Input Signal Missing ABS Module Go To Pinpoint Test F . C1236 Speed Wheel LR Input Signal Missing ABS Module Go To Pinpoint Test F . C1277 Steering Wheel Angle 1 and 2 Circuit Failure ABS Module Go To Pinpoint Test G . C1278 Steering Wheel Angle 1 and 2 Signal Faulted ABS Module Go To Pinpoint Test G . C1279 Yaw Rate Sensor Circuit Failure (Sensor Cluster Fault) ABS Module Go To Pinpoint Test H . C1280 Yaw Rate Sensor Signal Fault (Sensor Cluster Fault) ABS Module Go To Pinpoint Test H . C1281 Lateral Accelerometer Circuit Failure (Sensor Cluster Fault) ABS Module Go To Pinpoint Test H . C1282 Lateral Accelerometer Signal Fault (Sensor Cluster Fault) ABS Module Go To Pinpoint Test H . C1285 Booster Solenoid Circuit Failure ABS Module Go To Pinpoint Test I . C1287 Booster Pedal Force Switch Circuit Failure ABS Module Go To Pinpoint Test J . C1288 Pressure Sensor Main/Primary Input Circuit Failure ABS Module Go To Pinpoint Test K . C1440 (with stability assist) Pressure Sensor Main/Primary Signal Faulted ABS Module Go To Pinpoint Test K . C1516 Roll Rate Sensor Signal Fault (Sensor Cluster Fault) ABS Module Go To Pinpoint Test H . C1517 Roll Rate Sensor Circuit Failure (Sensor Cluster Fault) ABS Module Go To Pinpoint Test H . C1730 Reference Voltage Out of Range (+5V) ABS Module Go To Pinpoint Test L . C1805 Mismatched PCM and/or ABS-TC Module ABS Module CHECK for correct PCM and ABS module configuration using the diagnostic tool. RECONFIGURE the component as necessary. FOLLOW the diagnostic tool directions for the ABS module configuration or REFER to Section 303-01 for the PCM. CLEAR the DTC. REPEAT the self-test. C1963 Stability Control Inhibit Warning ABS Module This DTC is for information only. GO to the Principles of Operation. CLEAR the DTC. REPEAT the self-test. C1991 Module Calibration Failure ABS Module Follow the diagnostic tool directions for the calibration procedure. C1996 Active Yaw and/or Roll Control Disabled ABS Module This DTC can be set if the ABS module system is activated for 15 seconds of continuous operation. CHECK for any major chassis modifications, gross suspension misalignment or other items that can alter the vehicle tracking dynamics. CLEAR the DTC. REPEAT the self-test. C1998 Module Calibration Not Complete ABS Module Go To Pinpoint Test O . C2769 (ABS only) Longitudinal Acceleration Sensor Electrical Failure ABS Module INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module in this section. CLEAR the DTCs. REPEAT the self-test. C2769 (ABS with stability assist) Longitudinal Acceleration Sensor Electrical Failure (Sensor Cluster Fault) ABS Module Go To Pinpoint Test H . C2770 (ABS only) Longitudinal Acceleration Sensor Plausibility Failure ABS Module INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module in this section. CLEAR the DTCs. REPEAT the self-test. C2770 (ABS with stability assist) Longitudinal Acceleration Sensor Plausibility Failure (Sensor Cluster Fault) ABS Module Go To Pinpoint Test H . C2777 Sensor Cluster Bus Failure (Sensor Cluster Fault) ABS Module Go To Pinpoint Test H . C2778 Sensor Cluster Power Supply Failure (Sensor Cluster Fault) ABS Module Go To Pinpoint Test H . U1900 CAN Communication Bus Fault-Receive Error Network Fault REFER to Section 418-00 . U1901 CAN Network #2 Communication Bus Fault-Receive Error Network Fault Go To Pinpoint Test H . U2023 Fault Received from External Node Instrument Cluster REFER to Section 418-00 .

Wiring harness issues. the code doesn't men the sensor is the problem, it means a problem exists in the circuit of that sensor, that can be of course the sensor or the wiring or the computer. You need to the dealer to sort this out, a live data scanner is needed to look at the wheel speed sensors signal to see what is going on, that scanner costs big dollars. Many people yell and scream and call names when I suggest the dealer service dept, but that is what it takes so please don't shot the messenger. I speak form 35 years of experience.

ABS Fault Code List 1991 Corvette (C4)
Code Definition
21 Right Front Wheel Speed Sensor Fault
22 Right Front Toothed Wheel Frequency Error
25 Left Front Wheel Speed Sensor Fault
26 Left Front Toothed Wheel Frequency Error
31 Right Rear Wheel Speed Sensor Fault
32 Right Rear Toothed Wheel Frequency Error
35 Left Rear Wheel Speed Sensor Fault
36 Left Rear Toothed Wheel Frequency Error
41 Right Front Solenoid Valve Fault
45 Left Front Solenoid Valve Fault
55 Rear Wheels Solenoid Valve Fault
61 Pump Motor or Motor Relay Fault
63 Solenoid Valve Relay Fault
71 Electronic Brake Control Module Fault
72 Serial Data Line Fault
75 Lateral Accelerometer Fault (Short ot Open)
76 Lateral Accelerometer Fault (Signal out of Range)

It is part of the bearing hub assembly.Very have to do without air tools,If setting multiple abs/tc code (wheel speed sensors) probably abs electronic module or chaffed wires on drivers side at ac lines by air box.Have big problems with this and probably will come back.

I would pull the fuse for the ABS hydraulic pump and then put it back in and see what happens. Don't ever recall a pump running. Dealer may need to hook up scan tool for diagnostic fault codes, DTCs.



Principles of Operation
The ABS control module receives wheel speed readings from both front wheel speed sensors and the rear differential speed sensor, and processes this information to determine if an ABS event is necessary. The wheel speed sensor electrically senses each tooth of the ABS sensor indicators as it passes through the wheel speed sensor's magnetic field.
The ABS control module continuously monitors and compares the rotational speed of each wheel speed sensor indicator and, when it detects an impending wheel lock, modulates brake pressure to the appropriate brake caliper(s). This is accomplished by triggering the hydraulic control unit (HCU) to open and close the appropriate solenoid valves. Once the affected wheel returns to normal speed, the ABS control module returns the solenoid valves to their normal position, and normal (base) braking resumes.
The ABS control module is self-monitoring. When the ignition switch is turned to the RUN position, the ABS control module will do a preliminary electrical check, and at approximately 20 km/h (12 mph), the pump motor is turned on for approximately one-half second. Any malfunction of the ABS system will cause the ABS to shut off; normal power assisted braking, however, remains.
Inspection and Verification — Scan Tool Communications Check

1. Verify the customer concern by carrying out the Drive Cycle Test.

1. Visually inspect for obvious signs of mechanical and electrical damage.

Visual Inspection Chart Mechanical Electrical

• Parking brake cable
• Tire pressure
• Tire size or mismatched tires

• Blown fuse
• Central junction box (CJB):
  • fuse 23 (10A)
• Battery junction box
  • fuse 102 (50A)
• Connectors or connections
• Ground integrity
• Harness routing
• Wire chafing
• Circuitry open/shorted

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Anti-Lock Control The four-wheel anti-lock brake system (4WABS) consists of the following components:

• Anti-lock brake control module (2C265)
• Front anti-lock brake sensor (2C204)
• Front anti-lock brake sensor indicator (2C182)
• Hydraulic control unit (2C219)
• Rear anti-lock brake sensor (2C190)
• Rear anti-lock brake sensor indicator (2C189)
• Yellow ABS warning indicator