Volvo VN (VNL/VNM) Workshop Manual. Wiring Diagram

A complete technical manual on electrical circuit diagrams for Volvo VN series trucks, including VNL and VNM models. The manual is intended for service station specialists, electricians and owners involved in the maintenance and repair of electrical equipment of Volvo trucks manufactured in North America.

Volvo VNL (incl. 300, 430, 670, 760, 860)

Volvo VNM (200, 430, Day Cab and Sleeper Cab)

Modifications with D11, D13, D16 engines and I-Shift, Eaton Fuller gearboxes

• Wiring diagrams of control units (ECU)
• Pinout of connectors, cables and harnesses
• Power supply and grounding (Ground & Power Distribution)
• Lighting system, brake lights, turn signals
• Connection of sensors, valves, relays
• CAN bus, diagnostics and communication interfaces
• Decoding of symbols and color marking of wires
• Positions of relays and fuses on block diagrams
• Voltage and tolerance specifications

• General>>
• Volvo Home Page>>

MID SID Description

128 146 Low Oil Pressure

136 254 Instrument Cluster Communication Lost

144 91 Intake Temperature Error

130 2 Rear Wheel ABS Sensor Error

140 3 Transmission Communication Error

1. 🔋 Electrics and harnesses

Problem: Corrosion of contacts, broken wiring, EECU failures

Significance: Spontaneous errors on the panel, failure of light, HVAC, tachograph

Reason: Moisture, road salts, vibrations, overheating of harnesses

Advice: Regular diagnostics, replacement of rotten connectors, sealing

2. 💨 Pneumatic system

Problem: Air leaks, slow pressure build-up

Significance: Frequent compressor start-up, ABS errors, brake failures

Reason: Wear of fittings, leaking valves (e.g. in a tractor/trailer)

Advice: Use a soap solution to detect leaks, service the dehydrator

3. 🛑 EBS/ABS – Electronic braking system

Problem: ABS failures, "ABS" lights up or "Brake"

Reason: Broken or dirty sensors on the hubs

Solution: Cleaning/replacing sensors, checking cables

4. 🖥️ ECM and CAN bus communications

Problem: Loss of communication between control units

Manifestation: "NO COMM", MID/SID errors in diagnostics

Reason: Weak grounds, damaged CAN lines

Advice: Checking connectors, 60 Ohm resistance on CAN (normal)

5. 🌡️ Engine cooling system

Problem: Overheating, coolant leaks

Advice: Fan operation, loss of power

Reason: Wear of pump, radiator, leaking hoses

Advice: Check the condition of the reservoir, hoses and coolant level

6. 🛞 Front suspension / steering

Problem: Play in steering, uneven tire wear

Reason: Wear of kingpins, rods, shock absorbers

Solution: Regular adjustment and alignment check

7. ⚙️ I-Shift (if installed)

Problem: Delays when shifting, transmission error

Reason: Wear of clutch actuator, low oil level in the box

Solution: Clutch service, calibration via Tech Tool