Chassis, generic

C0018 Left Rear Inlet Control

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

Covers the left rear inlet (apply) solenoid valve of the ABS hydraulic modulator, the rear-axle counterpart of C0010. The module closes this valve to isolate the left rear brake circuit and hold wheel pressure during ABS, traction or stability control, then opens it to reapply pressure. On many vehicles the rear channel also carries electronic brake-force distribution. The module monitors the coil for opens, shorts to supply or ground and resistance outside the calibrated range. A confirmed electrical fault disables ABS and the stability functions and lights the ABS warning lamp while leaving base braking intact. No manufacturer documents this code publicly; NHTSA's brake safety study and a pump patent describe the per-wheel apply valve.

Likely causes

Inlet valve coil open or shorted
Harness or connector corrosion
Internal hydraulic modulator fault

Symptoms

  • ABS warning lamp on
  • ABS and stability control disabled
  • Normal braking retained

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€300–1,700
Time1.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

lr abs inlet valve

Related codes

C0019C001AC001C

References: rosap.ntl.bts.gov, patents.google.com, en.wikipedia.org.