P1184

Code

DS P — Powertrain

Vacuum monitoring short circuit to positive

Brand: DS

Type: P — Powertrain

Views: UK: 2 EN: 8 RU: 4

AI status

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Page language: EN

MIL (Check Engine Light) illuminated
Possible reduced engine performance or limp strategy depending on system
Erratic vacuum/MAP readings or frozen high signal on live data
Related systems dependent on vacuum reading may behave incorrectly (idle, boost control, fuel trim)
Usually no audible click; driving may be normal aside from MIL

Retrieve freeze-frame and full scan-tool live data for the vacuum sensor signal and reference voltages
Visually inspect sensor connector and wiring for damage, corrosion, or foreign objects
Backprobe sensor signal, reference (usually 5V) and ground with a digital multimeter or scope
Compare sensor signal voltage to expected range while varying engine vacuum (idle, rev, vacuum pump)
Check continuity from the signal wire to ECM and for unintended continuity to 12V with ignition OFF
Inspect nearby harness routing and aftermarket components that may contact the circuit

Typical reference supply: 5 V (model dependent). Expected signal: variable ~0.5–4.5 V according to vacuum/pressure
Short-to-positive symptom: signal reads near supply voltage (≈5 V) or possibly near battery voltage if circuit tied to 12 V
Open-circuit symptom: signal may read 0 V or float
Ground should be

Connect a scan tool, confirm P1184 and record freeze-frame and live data for the vacuum sensor, reference and ground pins.
Perform a visual inspection of the vacuum sensor, connector and harness from sensor to ECU for damage, corrosion, pin displacement or recent repair work.
With ignition ON (engine OFF), backprobe connector: verify reference voltage (usually 5 V), signal voltage and ground. Note if signal equals reference or battery voltage.
With ignition OFF, use a DMM to check continuity between the signal wire and battery positive. If there is continuity to 12 V with ignition OFF, trace and isolate the short.
Disconnect the sensor from the harness. Measure resistance from the signal pin to supply and ground on the harness side to locate short direction (sensor side vs harness/ECU side).
If harness side shows short to 12 V, disconnect intermediate connectors one at a time to localize the short. Inspect for chafing where harness passes near power feeds, fuse boxes or relays.
If harness is good, bench-test or replace the vacuum sensor. If replacement cures the fault, verify with live data and test drive.
If short persists after replacing sensor and repairing harness, suspect ECU/module fault and consult manufacturer repair information before replacing the module.
Perform proper repairs (replace wiring or sensor, solder and seal splices, use correct connectors), clear codes and perform a road test to confirm repair.

Wiring harness insulation rubbed through where routed near 12V feed or chassis
Connector contamination or a bent/pushed pin touching a 12V terminal
Defective vacuum (MAP/boost/vacuum monitor) sensor internally shorted to its supply
Incorrect part installed or connector mis-mated during previous repair

⚠️ Status

Vacuum monitoring circuit short to positive detected — signal voltage higher than expected (short to supply).

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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