P0370 — Timing Reference High Resolution Signal “A” #

Note: The wording of this Diagnostic Trouble Code (DTC) may vary depending on the vehicle manufacturer. Always refer to your OEM (Original Equipment Manufacturer) service documentation for the most precise definition.

Known label variations for P0370:
• Timing Reference High Resolution Signal “A” Malfunction (General/GM)
• High Resolution Crankshaft Position Signal “A” Circuit (Ford)
• Engine Position System Performance Bank 1 (Chrysler/Jeep/Dodge)
• Crank/Cam Sensor High Res Signal Error (Toyota/Lexus)

Summary of code P0370 #

P0370 indicates that the engine control module (ECM, also called PCM or ECU) has detected a fault in the high resolution timing reference signal “A”. This signal comes from either the crankshaft position sensor or the camshaft position sensor, both of which are critical for engine timing. The high resolution aspect refers to a more detailed “picture” of the engine’s rotation, allowing precise control over ignition and fuel injection timing. When this signal is erratic, missing, or out of expected range, the ECM cannot control timing reliably, which may impact engine operation, starting, or performance. Prompt diagnosis is important to prevent further issues or drivability problems.

Common symptoms for code P0370 #

If your vehicle has set a P0370 code, you may notice a range of symptoms, depending on the severity and when the problem occurs. In some cases, the symptoms may be subtle; in others, they can be severe enough to leave you stranded. Here are the most frequent signs:

• Check Engine Light (CEL) illuminated
• Engine hard to start, or fails to start
• Rough idle or engine misfires
• Intermittent stalling
• Reduced engine power or “limp” mode
• Poor acceleration or hesitation
• Decreased fuel efficiency

Probable causes for code P0370 #

The most frequent causes of a P0370 code relate to issues with the sensors or wiring that generate the high resolution timing signal. The following list is ordered from most to least common:

1. Faulty crankshaft position sensor (or camshaft position sensor, depending on application)
2. Damaged, corroded, or loose wiring/connectors in the sensor circuit
3. Faulty reluctor ring or timing wheel (missing or damaged teeth)
4. Improper sensor gap or installation
5. ECM/PCM internal fault (rare)
6. Aftermarket parts not matching OEM specifications

Step-by-step diagnostic process for P0370 #

Diagnosing a P0370 code requires a systematic approach to avoid missed causes or unnecessary part replacement. Follow these steps:

• 1. Verify the code with a scan tool and check for related codes (especially P0335, P0340).
• 2. Visually inspect the crankshaft/camshaft sensors, connectors, and harness for signs of wear, corrosion, or damage.
• 3. Test sensor output using a multimeter or oscilloscope, following OEM procedures for resistance and waveform.
• 4. Check the sensor gap (distance between sensor and reluctor/tone wheel) and verify installation.
• 5. Inspect the reluctor ring or timing wheel for missing, bent, or dirty teeth.
• 6. Check power and ground at the sensor connector with a multimeter.
• 7. Test continuity and resistance of the wiring from the sensor to the ECM.
• 8. Replace faulty components as needed, clear the code, and retest.

Possible repairs for P0370 #

Depending on the root cause, several repairs may resolve a P0370 code. Address each cause methodically:

• Replace a faulty crankshaft or camshaft position sensor with an OEM-quality part
• Repair or replace damaged wiring harnesses or connectors
• Clean or replace the reluctor ring/timing wheel if teeth are missing or contaminated
• Correct the sensor installation or adjust the sensor gap to OEM specs
• Reflash or replace the ECM/PCM if proven faulty after all other checks

Can you drive with code P0370? #

It is not recommended to drive with a P0370 code active. While some vehicles may continue to run with limited symptoms, the risk of sudden stalling, hard starting, or total loss of power is significant. In worst-case scenarios, engine damage can occur if timing control is lost. For safety and to avoid further damage, address this code as soon as possible.

Vehicles most commonly affected by P0370 #

While P0370 can appear on nearly any OBD-II equipped vehicle, it is most frequently reported on certain models due to sensor placement or design. The following brands and models are more commonly associated:

• GM (Chevrolet, GMC, Cadillac, Buick, Pontiac)
• Ford (F-Series, Explorer, Mustang)
• Chrysler, Dodge, Jeep (RAM pickup, Grand Cherokee, Charger)
• Toyota/Lexus (Camry, Tacoma, 4Runner, IS series)
• Volkswagen/Audi (Passat, Jetta, A4)
• Honda/Acura (Accord, Odyssey, TL)

Common mistakes and best practices for P0370 #

Many technicians and DIYers encounter pitfalls when troubleshooting P0370. Here’s how to avoid them:

• Replacing sensors without checking wiring or reluctor ring condition
• Using cheap aftermarket sensors that do not meet OEM specs
• Overlooking sensor gap adjustment or proper installation
• Neglecting to clear codes and verify repair with a road test
• Ignoring related codes that could point to a shared root cause

Express FAQ — P0370 #

Q: Can a weak battery or alternator cause P0370?
A: Rarely, but low system voltage can sometimes disrupt sensor signals. Always check battery and charging system health if other electrical issues are noted.

Q: Do I need an OEM sensor, or will aftermarket work?
A: For most timing sensors, OEM or high-quality OE-equivalent parts are strongly recommended. Inferior aftermarket sensors can cause ongoing or intermittent issues.