1998 Chevy Silverado P1345 and P0174 Codes: Causes, Fixes, and Cold Weather Impact
I own a 1998 Chevrolet Silverado with a Vortec engine, currently logging over 356,500 miles. I've been driving this truck daily for work—often 80+ miles—and have maintained it meticulously. Recently, the check engine light has come on with diagnostic codes P1345 and P0174. This is the first time I've seen these codes, and since I drive in winter conditions (with temperatures dropping below freezing), I'm wondering if cold weather could be contributing. I start the truck by turning the key for 15 seconds before cranking—often it feels like it's about to start on the first try, but it usually starts on the second attempt. The transmission shifts smoothly and engine performance is otherwise excellent. I don't plan to replace the vehicle anytime soon, as I'm committed to keeping it running until it's no longer practical. My current thoughts: Replace the fuel filter, upgrade the air filter, and possibly inspect or replace the MAF sensor. However, my top priority is identifying the root cause of these codes—so I don’t waste time and money on unnecessary part replacements. Could P1345 (Crankshaft Position-Camshaft Position Correlation) be related to cold weather? Is it possible that a faulty cam or crankshaft position sensor, or improper valve timing, is causing the issue? I'm looking for clear, actionable advice—can these codes be resolved with basic tools and DIY methods, or do I need to take it to a professional? If so, I’m willing to pay whatever it takes. Please share your insights on how to diagnose and fix P1345 and P0174 in a 1998 Chevy Silverado. I'd greatly appreciate any guidance. Email: nelsssz.an@gmail.com Phone: (320) 527-3037 (available 24/7)
P1345 in a 1998 Chevy Silverado — Crankshaft Position and Camshaft Position Correlation Repair Importance: High (3/3), Repair Difficulty: Moderate (2/3) Possible Causes: - Engine mechanical issues, such as incorrect valve timing - Loose or damaged crankshaft position (CKP) sensor or camshaft position (CMP) sensor mounting - Faulty camshaft position sensor or crankshaft position sensor Diagnostic Notes: If this code appeared after recent engine work, verify proper mechanical timing. With the cam cover removed and cylinder #1 at top dead center (TDC), ensure that the darkened chain links align with the alignment marks on the exhaust and intake cam sprockets. If P1345 resets without performance issues but no clear cause is found, consider replacing the cam phaser actuator or its associated sprocket. When is this code triggered? The Powertrain Control Module (PCM) detects a mismatch between crankshaft and camshaft sensor signals—indicating out-of-phase timing. Possible Symptoms: - Check engine light illuminated - Difficulty starting the engine - Engine stalling during operation Technical Background: The Crankshaft Position (CKP) sensor is a variable reluctance sensor that detects seven pulses per crankshaft revolution. Six of these are spaced 60 degrees apart, with one at 10 degrees after a 60-degree slot—this 'sync pulse' helps synchronize ignition timing and fuel injection. The Camshaft Position (CMP) sensor reads six pulses per camshaft revolution using notches of varying sizes to identify individual cylinders. The PCM uses both signals to monitor the relationship between crank and cam, ensuring proper valve actuation and cylinder compression timing. A mismatch in these signals can trigger P1345. Note: Always inspect sensor connections and mounting integrity before replacing parts.