As a vintage car enthusiast or owner of a classic 1986 Dodge, understanding your vehicle’s diagnostic systems is crucial for maintenance and repair. While modern cars boast sophisticated OBD2 systems, vehicles from 1986, including Dodge models, were equipped with earlier diagnostic technologies. This guide will walk you through understanding the diagnostic codes for your 1986 Dodge, often referred to in searches as “1986 Dodge Obd2” despite technically being an OBD1 system, and how to retrieve and interpret these codes yourself.
Understanding On-Board Diagnostics in Your 1986 Dodge
It’s important to clarify that while you might search for “1986 dodge obd2”, vehicles manufactured in 1986 predate the widespread adoption of OBD2 (On-Board Diagnostics II), which became standard in the mid-1990s. Your 1986 Dodge likely utilizes an OBD1 (On-Board Diagnostics I) system, or a precursor to it. These early systems were less standardized and less comprehensive than OBD2, but they still provide valuable insights into your engine’s health.
The misconception of “1986 dodge obd2” often arises because car enthusiasts are familiar with the term OBD2 as the common diagnostic standard. However, for your 1986 Dodge, we need to focus on the diagnostic procedures and codes relevant to its era. Think of it as understanding the diagnostic language your classic Dodge speaks.
Retrieving Diagnostic Codes: The “Key Trick” for Older Dodge Models
Forget plugging in a scan tool – diagnosing your 1986 Dodge involves a bit of old-school ingenuity, often referred to as the “key trick.” This method allows you to access the stored diagnostic trouble codes (DTCs) directly through your vehicle’s “check engine” light or, in some newer models of the era, the digital odometer.
Here’s how to perform the “key trick” on older Dodge models, which is applicable to your 1986 vehicle:
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Start with the ignition OFF. Ensure your key is not in the ignition or is turned to the “lock” position.
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Within five seconds, cycle the ignition key. Turn the key to the “ON” position (just before starting the engine, where the dashboard lights illuminate), then back to “OFF,” then “ON,” then “OFF,” and finally “ON” again. The sequence is: ON-OFF-ON-OFF-ON. Remember, “ON” is not “Start,” and “OFF” is not “Lock.”
Image showing ignition key positions, highlighting ‘ON’ and ‘OFF’ for diagnostic code retrieval.
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Observe the “check engine” light. After completing the key cycle, watch the “check engine” light on your dashboard. It will begin to flash in a pattern.
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Count the flashes. The flashes represent two-digit error codes. For example, a code 23 would be indicated by two flashes, a pause, then three flashes (FLASH-FLASH [pause] FLASH-FLASH-FLASH [long pause]). Pay close attention to the pauses to differentiate between codes. A long pause signifies the end of a code, and a longer pause indicates the start of a new code or the end of the code sequence. Code 55, indicated by five flashes then five flashes, is the “end of codes” message and is a normal indication that the system is finished displaying codes. It is not an error.
Important Notes for Code Retrieval:
- Parking Brake: In some older models, you might need to engage the parking brake for the codes to display correctly.
- Blink Spacing: The timing between flashes in older systems might not be perfectly uniform. Be patient and focus on counting the flashes and recognizing the pauses. If you see a sequence like 23 23, it’s likely just a single code 55 (end of codes).
- Digital Odometer: Some slightly newer models from this era may display codes on the digital odometer instead of flashing the “check engine” light. Keep an eye on both if you are unsure.
- “Limp In” Mode: If the computer detects a major system failure, it might activate “Limp In” mode. This is a safety feature that allows you to drive the car to a mechanic by compensating for sensor failures, often by estimating data. A common symptom of “Limp In” mode in automatic transmissions is the loss of third and/or fourth gear.
Decoding OBD1 Error Codes for Your 1986 Dodge
Once you’ve retrieved the codes from your 1986 Dodge, the next step is to understand what they mean. OBD1 codes are two-digit numbers, and each number corresponds to a specific system or sensor issue. Below is a comprehensive list of OBD1 codes relevant to Chrysler vehicles, including Dodge models of the 1980s. Remember, this is a general guide, and specific codes might vary slightly depending on the exact model and engine.
OBD1 Trouble Codes (Chrysler/Dodge – Circa 1986 and Earlier):
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11: No ignition reference signal detected during cranking OR timing belt skipped one or more teeth; OR loss of either camshaft or crankshaft position sensor.
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12: Battery or computer recently disconnected. This code often appears after battery maintenance and may clear itself after driving.
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13: MAP (Manifold Absolute Pressure) sensor or vacuum line may not be working.
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14: MAP sensor voltage below .16V or over 4.96V.
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15: No speed/distance sensor signal.
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16: Loss of battery voltage detected with engine running.
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17: Engine stays cool too long (bad thermostat or coolant sensor?) OR 17 (1985 turbo only): knock sensor circuit.
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21: Oxygen sensor signal doesn’t change (stays at 4.3-4.5V). Probably bad oxygen sensor.
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22: Coolant sensor signal out of range – May have been disconnected to set timing.
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23: Incoming air temperature sensor may be bad.
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24: Throttle position sensor over 4.96V.
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25: Automatic Idle Speed (AIS) motor driver circuit shorted or target idle not reached.
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26: Peak injector circuit voltage has not been reached (need to check computer signals, voltage regulator, injectors).
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27: Injector circuit isn’t switching when it’s told to (TBI) OR (MPI) injector circuit #1 not switching right OR (turbo) injector circuit #2 not switching right OR (all 1990-) injector output driver not responding – check computer, connections.
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31: Bad evaporator purge solenoid circuit or driver.
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32: (1984 only) power loss/limited lamp or circuit OR 32 EGR gases not working (1988): – check vacuum, valve OR 32 (1990-92): computer didn’t see change in air/fuel ratio when EGR activated – check valve, vacuum lines, and EGR electrical.
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33: Air conditioning clutch relay circuit open or shorted (may be in the wide-open-throttle cutoff circuit or normal on early 80’s models if you don’t have air conditioning).
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34: (1984-86) EGR solenoid circuit shorted or open OR 34 (1987-1991) speed control shorted or open. Important for 1986 Dodge Owners: This code for 1986 specifically refers to the EGR solenoid circuit.
Diagram illustrating an EGR (Exhaust Gas Recirculation) valve system, relevant to code 34 on a 1986 Dodge.
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35: Cooling fan relay circuit open or shorted OR 35 idle switch motor fault – check connections.
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36 (turbo only): Wastegate control circuit open or shorted.
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37: Shift indicator light failure, 5-speed OR part throttle lock/unlock solenoid driver circuit (87-89) OR solenoid coil circuit (85-87 Turbo only) OR Trans temperature sensor voltage low (1995 and on).
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41: Alternator field control circuit open or shorted.
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42: Automatic shutdown relay circuit open or shorted OR 42 Fuel pump relay control circuit OR 42 Fuel level unit – no change over miles OR 42 Z1 voltage missing when autoshutdown circuit energized. (The Z1 voltage is the voltage of the circuits fed by the autoshutdown relay. This typically includes fuel pump and switched-battery feed to the ignition coil).
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43: Peak primary coil current not achieved with max dwell time OR 43 Cylinder misfire OR 43 Problem in power module to logic module interface.
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44: No FJ2 voltage present at logic board OR 44 Logic module self-diagnostics indicate problem OR 44 Battery temperature out of range.
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45: Turbo boost limit exceeded (engine was shut down by logic module).
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46: Battery voltage too high during charging or charging system voltage too low.
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47: Battery voltage too low and alternator output too low.
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51: Oxygen sensor stuck at lean position (this may be tripped by a bad MAP sensor system causing a rich condition. If you get hot rough idle and stalling, especially on deceleration, accompanied by flooded engine and difficulty restarting, that can be a bad MAP sensor causing the O2 sensor to try to compensate. If you get poor cold drivability, stumbling and bucking, and acceptable warm driving with poor gas mileage (a drop of 10 mpg or more), that is usually the O2 sensor. OR 51 (1984 turbo only): Internal logic module fault (’84 turbo only).
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52: Oxygen sensor stuck at rich position OR 52 (1984 turbo only): Internal logic module fault (’84 turbo only).
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53: Logic module internal problem.
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54: No sync pickup signal during engine rotation (turbo only) OR 54 Internal logic module fault (’84 turbo only) – or camshaft sensor/distributor timing.
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55: End of codes. (Normal – not an error)
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61: “Baro” (Barometric pressure) sensor open or shorted.
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62: EMR mileage cannot be stored in EEPROM OR PCM failure SRI mile not stored.
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63: Controller cannot write to EEPROM.
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64: Catalytic converter efficiency failure.
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65: Power steering switch failure.
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66: No CCD Message From TCM (Transmission Control Module) and/or No CCD Message From BCM (Body Control Module).
Important Disclaimer:
This list is not exhaustive but covers the most common OBD1 codes for Chrysler/Dodge vehicles around 1986. It’s compiled from various sources and intended as a troubleshooting aid, not a definitive repair manual. Computers in these older systems can sometimes misinterpret data or not detect certain issues. A code reader designed for OBD1 systems or a professional mechanic can provide more accurate and comprehensive diagnostics.
Beyond the Codes: Expert Diagnosis for Your Classic Dodge
While understanding OBD1 codes is a great starting point for DIY diagnostics on your 1986 Dodge, remember the limitations of these early systems. For complex issues or if you are unsure about interpreting the codes, consulting a qualified mechanic with experience in classic vehicles is always recommended.
Modern scan tools and experienced technicians can often delve deeper into the systems of your 1986 Dodge than the basic OBD1 system allows. They can perform more advanced tests and have a wealth of experience to draw upon when diagnosing vintage vehicles.
In Conclusion:
Diagnosing your 1986 Dodge doesn’t require OBD2 scanners. By using the “key trick” and understanding the OBD1 code system, you can gain valuable insights into your vehicle’s health. While the term “1986 dodge obd2” is a common search term, remember that your classic Dodge utilizes an earlier OBD1 system. Use this guide to retrieve and interpret codes, but always prioritize professional diagnosis for accurate repairs and to keep your classic Dodge running smoothly for years to come.
Disclaimer: This article is for informational purposes only and should not be considered a substitute for professional automotive advice. Always consult a qualified mechanic for diagnosis and repairs.
Source: Information adapted from Jeep Horizons.com post by ThePhantum.
