Check Engine Light

[ccso503]

OK so on a 87 the diagnostic port is obviously differnt than new code readers. How do you spark the thing to have the engine light flash a code?

[BowTieDude]

From Autozone repair guide:

 

 

Reading Trouble Codes

 

Once the integrity of the system is confirmed, enter the Diagnostic Mode and read any stored codes. To enter the diagnostic mode:

 

1.

 

Turn the ignition switch OFF. Locate the Assembly Line Diagnostic Link (ALDL), usually under the instrument panel. It may be within a plastic cover or housing labeled DIAGNOSTIC CONNECTOR. This link is used to communicate with the ECM.

2.

 

The code(s) stored in memory may be read either through the flashing of the dashboard warning lamp or through the use of a hand-held scan tool. If using the scan tool, connect it correctly to the ALDL.

3.

 

If reading codes via the dash warning lamp, use a small jumper wire to connect Terminal B of the ALDL to Terminal A. As the ALDL connector is viewed from the front, Terminal A is on the extreme right of the upper row; Terminal B is second from the right on the upper row.

4.

 

After the terminals are connected, turn the ignition switch to the ON position but do not start the engine. The dash warning lamp should begin to flash Code 12. The code will display as one flash, a pause and two flashes. Code 12 is not a fault code. It is used as a system acknowledgment or handshake code; its presence indicates that the ECM can communicate as requested. Code 12 is used to begin every diagnostic sequence. Some vehicles also use Code 12 after all diagnostic codes have been sent.

5.

 

After Code 12 has been transmitted 3 times, the fault codes, if any, will each be transmitted 3 times. The codes are stored and transmitted in numeric order from lowest to highest.

 

The order of codes in the memory does not indicate the order of occurrence.

 

6.

 

Switch the ignition OFF when finished with code retrieval or scan tool readings.

 

Due to increased battery draw, do not allow the vehicle to remain in the Diagnostic Mode for more than 30 minutes. If longer periods are necessary, connect a battery charger.

 

Clearing Trouble Codes

 

Stored fault codes may be erased from memory at any time by removing power from the ECM for at least 30 seconds. It may be necessary to clear stored codes during diagnosis to check for any recurrence during a test drive, but the stored codes must be written down when retrieved. The codes may still be required for subsequent troubleshooting. Whenever a repair is complete, the stored codes must be erased and the vehicle test driven to confirm correct operation and repair.

 

The ignition switch must be OFF any time power is disconnected or restored to the ECM. Severe damage may result if this precaution is not observed.

 

Depending on the electric distribution of the particular vehicle, power to the ECM may be disconnected by removing the ECM fuse in the fusebox, or disconnecting the positive battery terminal. Disconnecting the battery cables to clear codes is not recommended as this will also clear other memory data in the vehicle such as radio presets or clock.

[BowTieDude]

Trouble Code list:

 

 

 

CODE 12—No engine speed sensor reference pulses are being received by the ECM. This code is not stored in memory and will flash only while the fault is present. This code is normal when the ignition is on and the engine is not running.

*

 

Code 13—The ECM has detected a problem in the oxygen sensor circuit. The engine must run at part throttle for at least four minutes before this code will set.

*

 

Code 14—The ECM has detected a short in the coolant temperature sensor circuit. The engine must be running for at least two minutes before this code will set.

*

 

Code 15—The ECM has detected a open in the coolant temperature sensor circuit. The engine must be running for at least two minutes before this code will set.

*

 

Code 21—The ECM has detected that the throttle position sensor circuit voltage is high. This is and indication that the throttle position sensor is out of adjustment or an open in the circuit wiring has occurred. The engine must run for a least 30 seconds at idle before this code will set in the ECM's memory.

*

 

Code 22—The ECM has detected that the throttle position sensor circuit voltage is low. This is an indication that the throttle position sensor circuit is shorted to ground. The engine must run for at least 2 minutes at 1250 rpm before this code will set in the ECM's memory.

*

 

Code 23—The ECM has detected a short or open in the mixture control solenoid circuit on carbureted engines or the Manifold Air Temperature (MAT) signal is high indicating a open circuit on fuel injected vehicles.

*

 

Code 24—No vehicle speed sensor signals are being received by the ECM. This is an indication that the circuit has an open or is shorted to ground. For this code to set, the vehicle must operate at any speed for 10 seconds.

*

 

Code 25—The ECM has detected that the Manifold Air Temperature (MAT) signal is low indicating a short to ground on fuel injected vehicles.

*

 

Code 32—The barometric pressure circuit signal voltage is low.

*

 

Code 33—The ECM has detected low vacuum in the Manifold Absolute Pressure (MAP) sensor circuit.

*

 

Code 34—The ECM has detected a problem in the vacuum sensor or the manifold absolute pressure sensor circuit. The engine must run for at least 2 minutes at curb idle before this code will set in the ECM's memory.

*

 

Code 35—The ECM has detected a problem with the idle speed control circuit.

*

 

Code 41— No distributor reference pulses to the ECM at specified engine vacuum.

*

 

Code 42—Electronic spark timing bypass circuit is grounded or open.

*

 

Code 43—Electronic spark control retard signal for too long a time period; causes a retard in the electronic spark timing.

*

 

Code 44—The ECM has detected a lean exhaust condition. The engine must run for two minutes in closed loop operation before this code will set.

*

 

Code 45—The ECM has detected a rich exhaust condition. The engine must run for two minutes in closed loop operation before this code will set.

*

 

Code 51—Faulty or improperly installed PROM or calibration chip in the ECM. The ignition must be on for approximately 10 seconds before this code will set.

 

*

 

Code 53— Exhaust Gas Recirculation (EGR) valve vacuum sensor circuit. The ECM has seen an improper EGR valve vacuum.

*

 

Code 54—The ECM has detected a short in the mixture control solenoid and or a faulty ECM.

*

 

Code 55—The ECM has detected a problem with itself. Replacement of the ECM is required.