P0375
Timing Reference High Resolution Signal B Malfunction
If your vehicle's onboard computer has flagged the diagnostic trouble code P0375, it refers to a detected anomaly regarding "Timing Reference High Resolution Signal B Malfunction". This systemic engine fault needs a targeted check before symptoms expand.
Driver's Summary
When your OBD2 scanner shows P0375, the engine control module has flagged an issue specifically related to timing reference high resolution signal b malfunction. On the road, this usually shows up as poor engine performance, rough idle, hard start. Given the high severity of this code, continuing to drive risks significant mechanical damage. Have it diagnosed immediately.
Symptoms
Poor engine performance, rough idle, hard start
Common Causes
- Defective sensor B in injection pump or distributor
- Damaged sensor wiring
- Corrosion in connector
- Bad PCM
How to Fix
- 1 Replace sensor B
- 2 Repair wiring harness
- 3 Clean electrical connector
- 4 Test PCM
Technical Explanation
The PCM triggers P0375 after its internal monitoring routine detects that a specific circuit or sensor has exceeded its acceptable operating range. The PCM monitors crankshaft rotational velocity via the CKP sensor at a resolution of individual tooth gaps on the reluctor ring. A combustion event in each cylinder produces a measurable acceleration spike; its absence or weakness is flagged as a misfire event within a 200-revolution or 1000-revolution test window. Once confirmed, the code is stored as a permanent DTC and the MIL is activated. The freeze frame snapshot — recording RPM, load, coolant temperature, and fuel trim at fault detection — is also saved and is critical for accurate diagnosis.
Is It Safe to Drive?
Driving with an active P0375 fault risks accelerating damage to defective sensor b in injection pump or distributor and related components. The longer the fault persists, the more expensive the eventual repair becomes — what starts as a sensor or solenoid issue can escalate to major mechanical failure.
Mechanic's Pro Tip
Module replacement should always be the last resort for P0375 after exhaustively verifying all power supply circuits, ground connections, and communication bus wiring. Use a wiring diagram to locate all fuses, relays, and ground points for the affected module, and measure voltage drop on each ground with the circuit loaded. A module "failure" is frequently a corroded ground eyelet or a weak battery causing brownout conditions — fix these first and you'll save hundreds of dollars on an unnecessary module replacement.
Sensor replacement: 150 - 400