P1618: Manufacturer-Specific Code (Chrysler/Dodge/RAM: Sensor Reference Voltage 1 Erratic)
2 vehicles · 1 makes · $200-$700 repair
Most Reported On
P1618 is an OBD-II diagnostic trouble code meaning “Manufacturer-Specific Code (Chrysler/Dodge/RAM: Sensor Reference Voltage 1 Erratic).” P1618 is a manufacturer-specific powertrain code, most associated with Chrysler/Dodge/RAM. It generally indicates the PCM detected that the primary 5-volt sensor reference supply (Reference Voltage 1) is varying too much or too quickly. Many sensors share this reference, so an erratic supply can cause multiple sensor readings to fluctuate, leading to rough idle, stalling, or poor performance. The exact circuit should be confirmed against the specific vehicle's service data. This code is most commonly reported on 2001-2004 Volvo S60, and 2001-2004 Volvo XC70, with repair costs ranging from $200 to $700.
Common Causes
Typical Repair Cost
Based on 2 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P1618, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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FAQ
What does P1618 mean?
P1618 stands for "Manufacturer-Specific Code (Chrysler/Dodge/RAM: Sensor Reference Voltage 1 Erratic)." P1618 is a manufacturer-specific powertrain code, most associated with Chrysler/Dodge/RAM. It generally indicates the PCM detected that the primary 5-volt sensor reference supply (Reference Voltage 1) is varying too much or too quickly. Many sensors share this reference, so an erratic supply can cause multiple sensor readings to fluctuate, leading to rough idle, stalling, or poor performance. The exact circuit should be confirmed against the specific vehicle's service data.
What are the most common causes of P1618?
The most common causes of P1618 are: Shorted or chafed sensor reference wiring, A failing sensor loading down the 5V reference circuit, Corroded or loose sensor connectors, Water intrusion in a connector on the reference circuit, Poor ground affecting the reference supply, PCM internal fault (less common). The specific cause varies by vehicle.
How much does it cost to fix P1618?
Repair costs for P1618 range from $200 to $700, depending on the vehicle and root cause.
Which vehicles are affected by P1618?
Au7o has documented P1618 across 2 vehicle models from 1 manufacturers: Volvo.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.