ev-motor

Power Electronics Module

for 2023 Chevrolet Bolt EUV 65 kWh Single Motor FWD · FWD

Difficulty

Expert

Time

6.0 h

Tools

Steps

Remove and replace the Power Electronics Module (PEM) on a 2023 Chevrolet Bolt EUV, which controls power conversion between the high-voltage battery and electric motor.

Warnings

⚠️High-voltage system operates at up to 400V DC. Death or serious injury will result from contact with energized components. Only qualified technicians with high-voltage training should perform this procedure.

⚠️Wait minimum 5 minutes after de-energizing system before working on high-voltage components. Verify 0V with multimeter before touching any orange cables or connectors.

⚠️Never assume system is de-energized. Always verify with proper test equipment.

⚠PEM contains sensitive electronics. Avoid impact, dropping, or exposure to moisture. Handle only by mounting points.

⚠Use proper lifting technique or assistance when removing PEM - unit weighs approximately 35 lbs.

Tools required

High-voltage insulated gloves (class 0 or higher)Essential

Digital multimeter with high-voltage capabilityEssential

Torque wrench (5-100 Nm range)Essential

GM MDI or compatible diagnostic toolEssential

Socket set (metric)Essential

Panel removal tools

Wire brush for terminal cleaning

Dielectric grease

Vehicle lift or jack stands rated for EV weightEssential

High-voltage lockout/tagout deviceEssential

Parts

Power Electronics Module (PEM) × 1 — Use OEM specification
High-voltage connector seals × 3 — Use OEM specification
Thermal interface pad × 1 — Use OEM specification
PEM mounting gasket × 1 — Use OEM specification

Preparation

Ensure vehicle is on level surface with parking brake engaged and wheel chocks in place
Verify 12V battery is fully charged (critical for maintaining control module memory during service)
Connect GM MDI diagnostic tool and document any existing DTCs
Review vehicle service history for any previous high-voltage system work
Ensure high-voltage PPE is inspected and rated for minimum 500V
Place high-voltage warning signs on vehicle and work area
Remove driver-side floor mat and locate emergency disconnect beneath center console if emergency isolation is needed

Procedure

1
De-energize high-voltage system
Using diagnostic tool, command the high-voltage system to service mode. Disconnect 12V negative battery cable. Wait 5 minutes for high-voltage capacitors to discharge. Install lockout/tagout device on 12V battery to prevent reconnection.
2
Access Power Electronics Module
Raise vehicle on lift. Remove front underbody shield and engine compartment lower covers. The PEM is located at the front of the drive unit assembly, mounted to the motor housing. Remove air deflector panels as needed for access.
Torque spec
Cover Screws11 Nm (8 lb-ft)
3
Verify system de-energization
Don high-voltage insulated gloves. Using high-voltage capable multimeter, verify 0V DC across high-voltage battery terminals and at PEM input connector. Document voltage readings. Do not proceed if any voltage is detected - investigate and resolve before continuing.
4
Disconnect cooling system connections
Place drain pan beneath PEM. Disconnect coolant inlet and outlet hoses from PEM cooling plate by releasing quick-connect fittings. Expect approximately 1 quart of coolant drainage. Cap open fittings to prevent contamination.
⚠Coolant may be hot if vehicle was recently operated. Allow adequate cooling time.
5
Disconnect low-voltage connections
Disconnect PEM control module connector (gray 24-pin connector on top of PEM). Press release tab and pull straight back. Disconnect temperature sensor connectors (2) from PEM housing.
Torque spec
Connector Bolts7 Nm (5 lb-ft)
6
Remove high-voltage cable connections
Wearing high-voltage gloves, remove high-voltage connector cover. Remove bolts securing high-voltage input cable from battery (orange cable, top connection), three-phase motor cables (bottom connections, 3 cables), and DC link connector. Support cable weight to prevent strain on connectors. Mark cable positions for reassembly.
⚠️Even with system de-energized, treat all orange cables as live. Verify connections with multimeter before and after disconnection.
Torque spec
Connector Bolts7 Nm (5 lb-ft)
7
Remove PEM support bracket
Remove support bracket connecting PEM to drive unit housing. Remove two bolts securing bracket to PEM and two bolts securing bracket to motor housing. Retain bracket hardware for reinstallation.
Torque spec
Bracket Bolts20 Nm (15 lb-ft)
8
Remove PEM mounting fasteners
Remove four mounting bolts securing PEM to drive unit motor housing. Support PEM weight while removing final bolts. Note position of any alignment dowels or guide pins.
Torque spec
Mounting Bolts27 Nm (20 lb-ft)
9
Remove Power Electronics Module
Carefully pull PEM away from motor housing, ensuring all connectors are clear. The PEM may have thermal interface material bonding it to the housing - gently rock side to side if needed. Lower PEM from vehicle and place on clean, padded work surface. Do not allow PEM to impact or drop.
10
Prepare mounting surface and new PEM
Clean motor housing mounting surface, removing old thermal interface material and gasket residue with approved cleaner. Inspect mounting surface for damage or corrosion. Clean high-voltage connector terminals on motor and cables with wire brush. Apply new thermal interface pad to motor housing mounting surface. Inspect new PEM for shipping damage.
11
Install new Power Electronics Module
Install new PEM mounting gasket if equipped. Carefully position new PEM onto motor housing, aligning dowel pins and ensuring thermal pad seats properly. Start all four mounting bolts by hand before tightening to ensure proper alignment.
Torque spec
Mounting Bolts27 Nm (20 lb-ft)
12
Reinstall support bracket and high-voltage connections
Install PEM support bracket, torquing fasteners to specification. Install new high-voltage connector seals on all three connections. Reconnect high-voltage battery input cable, three-phase motor cables (verify correct phase sequence from markings), and DC link connector. Apply thin coat of dielectric grease to connector threads if specified by service manual.
⚠Cross-threading high-voltage connectors will damage expensive components. Start all threads by hand and ensure proper engagement.
Torque spec
Bracket Bolts20 Nm (15 lb-ft)
Connector Bolts7 Nm (5 lb-ft)
13
Reconnect low-voltage and cooling connections
Reconnect PEM control module connector and temperature sensor connectors, ensuring positive engagement with audible click. Reconnect coolant inlet and outlet hoses to PEM cooling plate, verifying quick-connect fittings are fully seated.
Torque spec
Connector Bolts7 Nm (5 lb-ft)
14
Complete installation and system initialization
Install high-voltage connector cover. Reinstall underbody shields and covers. Remove lockout/tagout device and reconnect 12V battery. Using diagnostic tool, perform PEM configuration and programming per GM service procedures. Clear service mode and enable high-voltage system. Check coolant level and top off as needed with DEX-COOL to proper level.
Torque spec
Cover Screws11 Nm (8 lb-ft)

Reassembly

Torque all fasteners to specified values in the sequence listed
Verify all high-voltage connector seals are properly installed before energizing system
Ensure all protective covers and shields are reinstalled - missing components create shock hazards
Do not assume proper operation without performing complete verification procedure

Verification

Using diagnostic tool, verify no high-voltage system DTCs are present
Perform high-voltage isolation test - minimum 500 megohms isolation resistance required
Verify PEM coolant flow by monitoring inlet/outlet temperatures with scan tool during operation
Start vehicle and verify READY light illuminates without warning messages
Monitor PEM temperature during 10-minute idle period - should remain below 65°C
Perform test drive including gentle acceleration and regenerative braking - verify smooth operation with no warning lights
Verify no coolant leaks at PEM connections after test drive
Scan for DTCs after test drive and verify all systems pass
Document PEM part number and configuration in vehicle service records