Toggle Side Panel

Shopping Cart

No products in the basket.

Shopping Cart

No products in the basket.

Close search
Home / DTC / C1504 — Pressure Switch

C1504 — Pressure Switch

Detailed page for trouble code C1504.

34,405codes
59brands
11,914generic
22,491specific
All codes P-codes (Powertrain) B-codes (Body) C-codes (Chassis) U-codes (Network/User) Tesla Alerts
Reset
Code

C1504

HYUNDAI C — Chassis

Pressure Switch

Brand: HYUNDAI
Type: C — Chassis
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open, short or intermittent wiring between the pressure switch and control module
  • Corroded, loose or damaged connector at the switch
  • Failed or sticking pressure switch (mechanical or electrical failure)
  • Low or excessive system pressure (hydraulic leak, blocked line, failed pump)
  • Contamination (fluid ingress) or mechanical damage to the switch
  • Faulty ABS/ESC/transmission control module or internal input circuit

Symptoms

  • ABS, ESC or traction control warning lamp illuminated
  • Brake or system warning lamp (depending on system) on instrument panel
  • Loss of ABS/ESC functionality or altered braking behavior under ABS events
  • Diagnostic Trouble Code stored and possible limp or reduced functionality
  • Intermittent warnings or faults that appear under vibration or after wet conditions

What to check

  • Read stored/active codes and freeze-frame data with a proper scan tool; note system and vehicle speed when fault set
  • Inspect wiring and connector at the pressure switch for corrosion, damage, or water intrusion
  • Backprobe the switch connector and check for correct reference voltage/supply and ground at key ON (see signal_params)
  • Measure switch continuity/resistance with switch actuated (apply system pressure or hand-actuate if possible)
  • Perform wiggle test on harness while monitoring live data for intermittent changes
  • Check related hydraulic/pneumatic system pressure with a gauge to confirm actual pressure vs expected

Signal parameters

  • Switch type: typically simple open/closed (mechanical contact) or 2–3 wire transducer depending on model
  • Continuity: closed (active) ~0–5 ohms; open (inactive) >>1 MΩ (when switch is not engaged) — verify with model-specific values
  • Voltage: if switch is pulled to ground when active, expect ~0 V at signal with switch closed and battery voltage (~12 V) when open (or vice versa for some designs)
  • Reference: some modules use a 5 V reference for transducers; others use switched 12 V for simple switches — confirm with vehicle wiring diagram
  • Activation pressure: varies by system; many automotive hydraulic pressure switches change state within a broad range (approx. 0.5–10 bar / 7–145 psi) — use manufacturer spec

Diagnostic algorithm

  1. Connect a full-function scan tool, record the fault, freeze-frame and live data. Note which system and input is affected.
  2. Visually inspect the switch, connector and harness. Repair chafed wiring or corroded terminals before further testing.
  3. Backprobe the connector: verify supply voltage and ground with key ON; compare to signal_params. If no supply, trace power/ground to the fuse/relay/module.
  4. Check switch continuity with multimeter while applying pressure to the system or manually actuating the switch. If continuity does not change at expected pressure, replace the switch.
  5. If continuity and supply are correct but signal stays erratic, perform a wiggle test on harness and recheck live data. Repair or replace harness/connector as required.
  6. Verify actual system pressure with a calibrated gauge to rule out low/high pressure causing correct but out-of-spec switch behavior.
  7. If wiring, connector and switch are good, check the control module input using pin-level diagnostics or substitute known-good module per service manual procedures.
  8. After repairs, clear codes and road-test to confirm the fault does not return. Re-scan to ensure no secondary codes are present.

Likely causes

  • Damaged wiring harness or chafed insulation to the switch
  • Corroded connector pins or poor pin seating at the switch
  • Failed pressure switch (most common after wiring/connector checks)
  • System pressure out of range due to leak or failed component
  • Intermittent contact from water/contamination causing false fault

Fault status

⚠️ Status
C1504 — Pressure switch circuit malfunction: open/short/intermittent signal or out-of-range pressure input to the control module.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5 - 2.0 hours

Similar codes

C1500 C1501 C1502 C1503 C1505
371

Browse 371 HYUNDAI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

HYUNDAI

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

Report

Harassment or bullying behavior
Contains mature or sensitive content
Contains misleading or false information
Contains abusive or derogatory content
Contains spam, fake content or potential malware

Block Member?

Please confirm you want to block this member.

You will no longer be able to:

  • See blocked member's posts
  • Mention this member in posts
  • Invite this member to groups
  • Message this member
  • Add this member as a connection

Please note: This action will also remove this member from your connections and send a report to the site admin. Please allow a few minutes for this process to complete.

Report

You have already reported this .