VIDEO: Lexus P0345 & P0348 Camshaft Position Sensor Codes: Finding a Poor Connector Connection
When a check engine light points to a sensor circuit, replacing the sensor isn’t always the answer. Sometimes the real problem is hidden inside the wiring or electrical connector.
At PROFIX Auto Repair in Norman, OK, we recently diagnosed P0345 and P0348 camshaft position sensor circuit high codes on this 1998 Lexus LS400. Instead of guessing and replacing parts, our technician tested the circuit and monitored the camshaft sensor signals with a lab scope to determine exactly what the vehicle’s computer was seeing.
Testing the Camshaft Position Sensor Circuit
The circuit was load-tested first to make sure the wiring itself could properly carry current. Those tests showed that the circuit was complete, which meant we needed to look more closely at the connection itself.
Using a scope, we monitored the camshaft position sensor signal while also checking the circuit at the ECU.
The test revealed something very specific: the 5-volt reference terminal was not making reliable contact inside the connector.
Our technician was able to demonstrate the failure in real time. With a test probe inserted into the terminal, contact was restored and the camshaft position sensor began producing the proper signal. Remove the probe, and the signal went high again. Reinsert it, and the sensor immediately began reporting normally.
The Problem Was Pin Fit — Not the Sensor
This is known as a poor pin fit or poor terminal connection.
Electrical connectors rely on very small metal terminals maintaining firm contact with one another. As vehicles age, terminals can loosen, spread, corrode, or otherwise lose proper contact. The wiring may appear fine and may even pass certain basic electrical tests, while the connection fails when everything is plugged together normally.
In this Lexus, correcting the terminal fit restored the connection and allowed the ECU to receive the proper camshaft position sensor signal.
Why Proper Electrical Diagnosis Matters
A trouble code tells a technician where the computer detected a problem — not necessarily which part needs to be replaced.
Codes such as P0345 and P0348 can involve the sensor itself, wiring, connectors, power or ground circuits, or problems with the signal reaching the ECU. Simply replacing a camshaft position sensor without testing the circuit could leave the original problem completely unresolved.
This is why we use tools such as lab scopes, circuit load testing, wiring diagrams, and direct ECU measurements when diagnosing difficult electrical problems.
Lexus & Toyota Diagnostics in Norman, OK
If your Lexus or Toyota has a check engine light, intermittent electrical problem, sensor circuit code, or another issue that hasn’t been easy to track down, PROFIX Auto Repair in Norman can help.
Our goal is to identify the actual cause of the problem before recommending repairs—not simply replace parts based on a trouble code.
PROFIX Auto Repair has two convenient Norman, Oklahoma locations and provides diagnostics, maintenance, and mechanical repair for Lexus, Toyota, and most other makes and models.
