E070

Code E70:

Sensor Circuit:

DESCRIPTION:

The diagnostic test monitors Manifold Pressure (MAP) and Throttle Angle (TPS). If the MAP remains constant and there is a large change in TPS, the code will set. Engine operation requires that, any large change in Throttle Angle (TPS) must be followed by a change in Manifold Pressure (MAP).

TEST CONDITIONS:

1. Codes E31, E32, and E34 not set.
2. Throttle angle changes more than 3.5° in 12.5 milliseconds (.0125 seconds).
3. Engine not decelerating where MAP becomes 22 kPa or less.
4. Engine is not accelerating where MAP is within 7.4 kPa of atmospheric pressure.
5. Engine running.

FAILURE CONDITIONS:

1. MAP changes 3.5° or less in .16 seconds following the change in throttle angle.

ACTION TAKEN:

1. Code E70 sets.
2. No "SERVICE ENGINE SOON" telltale.

NOTES ON FAULT TREE:

1. Because of the nature of this code, the fault is not present at this time unless a code E21, E22, E31, E32, or E34 is current. This code indicates an unacceptable high rate of TPS change, and is useful in diagnosing driveability conditions which otherwise would not set a code.

2. As the ISC extends, the TPS voltage as measured at the TPS jumper should increase at a steady reate. A dead spot in the TPS will cause the voltage to jump erratically as the ISC moves the TPS past that spot. For this test, a high impedance needle-type voltmeter may be used, as a quick deflection of the needle is easier to observe than with a digital meter.

3. If the throttle blades cannot return to the idle stop, the throttle valves may be coked or binding. These conditions may cause E55 and E85 to set.

4. Improper TPS adjustment such as forcing or tapping on the TPS without loosening the attaching screws, will damage the TPS and can cause code E70 to set.

NOTE ON INTERMITTENTS:

If an intermittent TPS condition cannot be induced with the trouble tree, manipulate the TPS connector, TPS witing and PCM connector while observing PCM data P.0.1 (or scan tool display). Check the TPS and TPS jumper connectors for opens or shorts to voltage. Cycle the TPS through its travel and lightly tap on the TPS with a pencil or pocket screwdriver while watching the display to test for an intermittent. If a fault is induced, PCM data P.0.1 will momentarily skip to 72 degrees or greater, or 1.3 degrees or less. If wiring and connector check out OK, substitute a known good TPS and recheck.