Ford Trouble Codes OBD1

This article contains Ford OBD1 trouble codes definitions and retrieval method.

Ford vehicles manufactured before 1996 has the OBD 1 system which is unique in the way trouble codes are retrieved. Before retrieving codes have the engine heated to operating temperature.

Step 1 - Use a grounded test light inserted into the data link connector, which is usually under the hood near the battery.

 Ford OBD1 Connector
Ford Data Link Connector Code Gathering Mode

Step 2 - Turn the key to the" ON" position this will initiate the code gathering sequence which be produced in the form of two digits.

Step 3 - The test light will begin to flash on, then off, when the flashing stops the first digit is complete, the system will then pause, and the second digit will begin. Example: Test light flashes twice, and pauses, then flashes six more times the code number is 26.

Step 4 - Once repairs have been made, to clear system, simply remove the negative battery cable for thirty seconds and reconnect.

Codes for OBD1 (Before 1995)

11 - System pass

12 - Idle control fault

13 - DC motor did not move

14 - engine rpm signal fault or PIP circuit failure

15 - EEC processor or power to KAM interrupted

16 - rpm to low to check oxygen sensor test or fuel control error

17 - CFI fuel control system fault or rich/lean condition indicated

18 - Ignition diagnostic monitor (IDM) circuit failure

19 - Cylinder identification (CID) sensor input failure

21 - Engine coolant temperature (ECT) out of self-test range

22 - Manifold absolute pressure (MAP) sensor circuit out of range

23 - Throttle position sensor out of self-test range

24 - Air charge temperature (ACT) sensor out of self-test range

25 - Knock not sensed during dynamic response test

26 - Transmission fluid temperature out of self-test range

28 - Loss of primary tach, right side

29 - Insufficient input from vehicle speed sensor

31 - EGR position sensor below minimum voltage

32 - EGR position sensor below closed limit

33 - Throttle position sensor noisy/harsh on line

34 - EGR valve circuit out of self-test range

35 - EGR valve circuit above maximum voltage

38 - Idle track switch circuit open

39 - AXOD torque converter or bypass clutch not applying properly

41 - Oxygen sensor circuit indicates system always lean

42 - Oxygen sensor circuit indicates system always rich

43 - Oxygen sensor out of self-test range

44 - Air injection control system failure

45 - Coil 1 primary circuit failure

46 - Coil primary circuit failure

47  - 4X4 switch is closed or oxygen sensor failure

48 - Coil primary circuit failure

49 - Electronic transmission shift error

51 - Engine coolant temperature sensor circuit open

52 - Power steering pressure switch circuit open

53 - Throttle position circuit above maximum voltage

54 - Air charge temperature circuit open

55 - Key power input to processor open circuit

56 - Mass air flow circuit above maximum voltage

57 - AXOD circuit failure

58 - Idle tracking switch circuit fault

59 - Automatic transmission shift error

61 - Engine coolant temperature circuit grounded

62 - Converter clutch error

63 - Throttle position circuit below minimum voltage

64 - Air charge temperature circuit grounded

65 - Charging system over voltage

66 - Mass air flow sensor circuit below minimum voltage

67 - Neutral/drive switch circuit open

68 - Transmission fluid temperature over temperature transmission shift error

70 - Data circuit communication link circuit failure

71 - Message center circuit circuit failure

72 - Insufficient manifold absolute pressure (MAP) change during dynamic response test

73 - Insufficient throttle position (TPS) change during dynamic response test

74 - Brake on/off (BOO) circuit open

75 - Brake on/off (BOO) circuit closed

76 - Insufficient air flow output change during test

77 - Brief wide open throttle not sensed during test

78 - Power interrupt detected

79 - A/C on/defrost on during self test

81 - Map has not changed normally

82 - Super charger bypass circuit failure

83 - OIC-low speed fuel pump relay circuit failure

84 - EGR vacuum regulator (EVR) circuit failure

85 - Canister purge circuit failure

86 - Shift solenoid circuit failure

87 - Fuel pump circuit failure

88 - Electro drive fan circuit failure

89 - Transmission solenoid circuit failure

91 - No oxygen sensor switching detected

92 - Shift solenoid circuit failure

93 - Throttle position sensor input low

94 - Torque converter clutch solenoid circuit failure

95 - Fuel pump secondary circuit failure

96 - Fuel pump secondary circuit failure

97 - Transmission indicator circuit failure

98 - Electronic pressure control circuit failure

99 - EEC has not learned to control idle


Written by
Co-Founder and CEO of
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2013-11-10)