Code
C0498
HUMMER
C — Chassis
Steering Assist Control Actuator Feed Circuit Low
Views:
UK: 12
EN: 14
RU: 9
AI status
Completed
Completed
100%
Causes
- Blown or corroded fuse protecting the steering assist feed
- Weak or discharged battery or poor battery connections
- Poor or corroded connector or pin at the actuator or control module
- Open or shorted wiring in the feed circuit (short to ground)
- Faulty steering assist actuator (internal short or high internal load)
- Faulty steering control module or power relay
Symptoms
- Reduced or no power steering assist (hard steering)
- Steering warning lamp or message on instrument cluster
- DTC C0498 stored in chassis/steering module
- Intermittent loss of assist or assist returns after vehicle restart
- Other electrical oddities if battery/charging is weak (dim lights, slow cranking)
What to check
- Read and record all related DTCs from steering and body modules; note freeze frame data
- Check battery voltage with key OFF and key ON (resting and system voltage under load)
- Visually inspect fuses and steering assist power/relay circuits; test or swap relay if applicable
- Inspect connectors and wiring at the actuator and steering control module for corrosion, bent pins, water intrusion, or damage
- Back-probe actuator power feed connector and measure voltage with key in ON/Run while commanding assist if possible
- Perform wiggle test on harness while monitoring voltage and DTC status to reveal intermittent faults
Signal parameters
- Expected feed (B+) voltage at actuator connector with key ON: approximately battery voltage (11–14.5 V depending on charge state)
- Voltage under actuator command: may drop but should not fall near 0 V; significant drop under load indicates excessive current draw or high resistance
- Resistance of power feed circuit to battery positive: should be low (single-digit ohms including relay); isolated open will show very high/OL
- Ground circuit continuity: near 0 ohms between actuator ground and chassis ground
Diagnostic algorithm
- Confirm C0498 is active. Retrieve freeze frame and any related steering codes. Note ignition state and vehicle speed when fault recorded.
- Check battery state of charge and terminal condition. Charge or replace battery if voltage is low. Clean and tighten battery terminals.
- Inspect and test fuses and steering assist power relay. Replace any blown fuses; swap relay with a known-good identical relay if available.
- With key ON (engine off for safety), back-probe the actuator power feed pin and measure voltage. If voltage is significantly below battery, suspect feed/relay/connection or high current draw.
- If low voltage at connector, trace back wiring to steering control module/relay/fuse. Visually inspect harness, and perform continuity/resistance checks to locate high resistance or open.
- Check ground(s) for the actuator and related modules. Clean and secure ground connections; verify continuity to chassis.
- If wiring checks good at rest but voltage drops under command, measure current draw (clamp meter) during actuator operation. Excessive current indicates internal actuator fault or mechanical binding.
- If wiring and power/ground are within specification, consider replacing the actuator or steering control module per manufacturer service manual. Re-test after repair and clear codes. Monitor for return of fault.
Likely causes
- Loose or corroded battery positive terminal or ground reducing system voltage
- Blown fuse or failed power relay feeding the actuator
- Damaged wire or connector between the steering control module and actuator (pin corrosion or broken wire)
- Actuator internal failure presenting as excessive current draw and voltage drop
Fault status
Status
Steering Assist Control Actuator Feed Circuit Low — the steering control module detected the actuator power feed voltage is below expected thresholds and stored DTC C0498. Assist may be reduced or disabled until the fault is corrected.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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