The Diagnostic Trouble Codes (DTCs) listed below are some of the most commonly reported on GM vehicles 1996 and newer. The SUPER AutoScanner Kit CP9150 and the SUPER AutoScanner CP9145 can retrieve both Generic and Enhanced DTCs to the tool. Although the CP9135 is not designed to retrieve these enhanced codes, many GM vehicles will send both generic and enhanced codes as well.

Please note that these DTC definitions are provided for reference only. We recommend that you consult a service manual for your vehicle before actually attempting repairs.

If the definition of your code is not listed below, you can use our online code lookup application:
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You can also call our Technical Support department at 1-800-228-7667 (8:00 - 6:00 EST, Monday - Friday), or email your request to cleveland_tech@servicesolutions.spx.com.

Many of the larger public library systems keep a fairly complete inventory of factory service manuals in their reference sections. These manuals will contain code definitions and other troubleshooting information that can be very helpful.

To order a book containing a complete list of codes for GM, Ford and Chrysler or Asian OBD II vehicles, please visit www.autodatapubs.com.

P1133 B1 S1 Insufficient Switching Condition
An O2 sensor being damaged usually causes this. In most cases, it will require replacement. Wiring connections should be checked before replacing the O2 sensor.

P1139 B1 S2 Insufficient Switching Condition
An O2 sensor being damaged usually causes this. In most cases, it will require replacement. Wiring connections should be checked before replacing the O2 sensor.

P1153 B2 S1 Insufficient Switching Condition
An O2 sensor being damaged usually causes this. In most cases, it will require replacement. Wiring connections should be checked before replacing the O2 sensor.

P1345 Camshaft to Crankshaft Position Correlation Fault
This code is typically set because the camshaft sensor is not properly synchronized with the crankshaft sensor. Wiring and/or connector faults with either the camshaft or crankshaft sensors can set this code. A sensor tester or multimeter can be used to verify that a proper signal is reaching the engine computer. If the distributor has been removed and not reset or reinstalled properly, use a scan tool to monitor the "Cam Counts" and set them as close to zero as possible by adjusting or repositioning the distributor.

P1404 Exhaust Gas Recirculation Error
This code is typically caused by carbon buildup in the EGR valve. The carbon deposits prevent the valve from closing completely. After removing the EGR valve, clean the pintle seat area of the valve and the corresponding passageway in the engine.

P1406 EGR Valve Pintle Position Circuit Fault
This code is typically caused by carbon buildup in the EGR valve. The carbon deposits prevent the valve from closing completely. After removing the EGR valve, clean the pintle seat area of the valve and the corresponding passageway in the engine.

P1415 Secondary Air Injection System (Bank 1) Condition
This relates to several different components. Older vehicles used a mechanically driven air pump. Newer vehicles have an electric pump. The air pump, air solenoid valve, and vacuum lines are all possible causes. Poor wire connections, or broken or damaged wires can also be at fault.

P1416 Secondary Air Injection System (Bank 2) Condition
This relates to several different components. Older vehicles used a mechanically driven air pump. Newer vehicles have an electric pump. The air pump, air solenoid valve, and vacuum lines are all possible causes. Poor wire connections, or broken or damaged wires can also be at fault.

P1441 EVAP System Flow During Non-Purge Conditions.
This deals with the purge solenoid, vent solenoid, charcoal canister, all the vacuum lines in this system, as well as the gas cap. Any one of these components may contribute to this code being set. All the wiring should be tested including the connectors for any problems. Vacuum lines should be checked for cracks or loose connections. The canister may be damaged or not working properly.

P1642 Secondary Air System Control Circuit
This relates to several different components. Older vehicles used a mechanically driven air pump. Newer vehicles have an electric pump. The air pump, air solenoid valve, and vacuum lines are all possible causes. Poor wire connections, or broken or damaged wires can also be at fault.

P1870 Internal Transmission Component Slipping
This code is often set due to overheating inside the transmission. Extended periods of stop and go driving may also cause this code. Common symptoms associated with this code are harsh shifting from first to second gear and/or no overdrive or fourth gear. These symptoms are caused by an increase in transmission pressure in order to compensate for the internal slippage. Sometimes a complete transmission service including a fluid flush and refill can remedy this problem. In extreme cases, a transmission rebuild or replacement is required.